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Technology Short Take #34

Welcome to Technology Short Take #34, my latest collection of links, articles, thoughts, and ideas from around the web, centered on key data center technologies. Enjoy!

Networking

  • Henry Louwers has a nice write-up on some of the design considerations that go into selecting a Citrix NetScaler solution.
  • Scott Hogg explores jumbo frames and their benefits/drawbacks in a clear and concise manner. It’s worth reading if you aren’t familiar with jumbo frames and some of the considerations around their use.
  • The networking “old guard” likes to talk about how x86 servers and virtualization create network bottlenecks due to performance concerns, but as Ivan points out in this post, it’s rapidly becoming—or has already become—a non-issue. (By the way, if you’re not already reading all of Ivan’s content, you need to be. Seriously.)
  • Greg Ferro, aka EtherealMind, has a great series of articles on overlay networking (a component technology used in a number of network virtualization solutions). Greg starts out with a quick look at the value prop for overlay networking. In addition to highlighting one key value of overlay networking—that decoupling the logical network from the physical network enables more rapid change and innovation—Greg also establishes that overlay networking is not new. Greg continues with a more detailed look at how overlay networking works. Finally, Greg takes a look at whether overlay networking and the physical network should be integrated; he arrives at the conclusion that integrating the two is likely to be unsuccessful given the history of such attempts in the past.
  • Terry Slattery ruminates on the power of creating (and using) the right abstraction in networking. The value of the “right abstraction” has come up a number of times; it was a featured discussion point of Martin Casado’s talk at the OpenStack Summit in Portland in April, and takes center stage in a recent post over at Network Heresy.
  • Here’s a decent two-part series about running Vyatta on VMware Workstation (part 1 and part 2).
  • Could we use OpenFlow to build better internet exchanges? Here’s one idea.

Servers/Hardware

Security

I have nothing to share this time around, but I’ll keep watch for content to include in future Technology Short Takes.

Cloud Computing/Cloud Management

  • Tom Fojta takes a look at integrating vCloud Automation Center (vCAC) with vCloud Director in this post. (By the way, congrats to Tom on becoming the first VCDX-Cloud!)
  • In case you missed it, here’s the recording for the #vBrownBag session with Jon Harris on vCAC. (I had the opportunity to hear Jon speak about his employer’s vCAC deployment and some of the lessons learned at a recent New Mexico VMUG meeting.)

Operating Systems/Applications

Storage

  • Rawlinson Rivera starts to address a lack of available information about Virsto in the first of a series of posts on VMware Virsto. This initial post provides an introduction to Virsto; future posts will provide more in-depth technical details (which is what I’m really looking forward to getting).
  • Nigel Poulton talks a bit about target driven zoning, something I’ve mentioned before on this site. For more information on target driven zoning (also referred to as peer zoning), also be sure to check out Erik Smith’s blog.
  • Now that he’s had some time to come up to speed in his new role, Frank Denneman has started a great series on the basic elements of PernixData’s Flash Virtualization Platform (FVP). You can read part 1 here and part 2 here. I’m looking forward to future parts in this series.
  • I’d often wondered this myself, and now Cormac Hogan has the answer: why is uploading files to VMFS so slow? Good information.

Virtualization

It’s time to wrap up now, or this Technology Short Take is going to turn into a Technology Long Take. Anyway, I hope you found something useful in this little collection. If you have any feedback or suggestions for improvement for future posts, feel free to speak up in the comments below.

Technology Short Take #33

Welcome to Technology Short Take #33, the latest in my irregularly-published series of articles discussing various data center technology-related links, articles, rants, thoughts, and questions. I hope that you find something useful here. Enjoy!

Networking

  • Tom Nolle asks the question, “Is virtualization reality even more elusive than virtual reality?” It’s a good read; the key thing that I took away from it was that SDN, NFV, and related efforts are great, but what we really need is something that can pull all these together in a way that customers (and providers) reap the benefits.
  • What happens when multiple VXLAN logical networks are mapped to the same multicast group? Venky explains it in this post. Venky also has a great write-up on how the VTEP (VXLAN Tunnel End Point) learns and creates the forwarding table.
  • This post by Ranga Maddipudi shows you how to use App Firewall in conjunction with VXLAN logical networks.
  • Jason Edelman is on a roll with a couple of great blog posts. First up, Jason goes off on a rant about network virtualization, briefly hitting topics like the relationship between overlays and hardware, the role of hardware in network virtualization, the changing roles of data center professionals, and whether overlays are the next logical step in the evolution of the network. I particularly enjoyed the snippet from the post by Bill Koss. Next, Jason dives a bit deeper on the relationship between network overlays and hardware, and shares his thoughts on where it does—and doesn’t—make sense to have hardware terminating overlay tunnels.
  • Another post by Tom Nolle explores the relationship—complicated at times—between SDN, NFV, and the cloud. Given that we define the cloud (sorry to steal your phrase, Joe) as elastic, pooled resources with self-service functionality and ubiquitous access, I can see where Tom states that to discuss SDN or NFV without discussing cloud is silly. On the flip side, though, I have to believe that it’s possible for organizations to make a gradual shift in their computing architectures and processes, so one almost has to discuss these various components individually, because to tie them all together makes it almost impossible. Thoughts?
  • If you haven’t already introduced yourself to VXLAN (one of several draft protocols used as an overlay protocol), Cisco Inferno has a reasonable write-up.
  • I know Steve Jin, and he’s a really smart guy. I must disagree with some of his statements regarding what software-defined networking is and is not and where it fits, written back in April. I talked before about the difference between network virtualization and SDN, so no need to mention that again. Also, the two key flaws that Steve identifies—single point of failure and scalability—aren’t flaws with SDN/network virtualization, but rather flaws in an implementation of said technologies, IMHO.

Servers/Hardware

  • Correction from the last Technology Short Take—I incorrectly stated that the HP Moonshot offerings were ARM-based, and therefore wouldn’t support vSphere. I was wrong. The servers (right now, at least) are running Intel Atom S1260 CPUs, which are x86-based and do offer features like Intel VT-x. Thanks to all who pointed this out, and my apologies for the error!
  • I missed this on the #vBrownBag series: designing HP Virtual Connect for vSphere 5.x.

Security

Cloud Computing/Cloud Management

  • Hyper-V as hypervisor with OpenStack Compute? Sure, see here.
  • Cody Bunch, who has been focusing quite a bit on OpenStack recently, has a nice write-up on using Razor and Chef to automate an OpenStack build. Part 1 is here; part 2 is here. Good stuff—keep it up, Cody!
  • I’ve mentioned in some of my OpenStack presentations (see SpeakerDeck or Slideshare) that a great place to start if you’re just getting started is DevStack. Here, Brent Salisbury has a nice write-up on using DevStack to install OpenStack Grizzly.

Operating Systems/Applications

  • Boxen, a tool created by GitHub to manage their OS X Mountain Lion laptops for developers, looks interesting. Might be a useful tool for other environments, too.
  • If you use TextMate2 (I switched to BBEdit a little while ago after being a long-time TextMate user), you might enjoy this quick post by Colin McNamara on Puppet syntax highlighting using TextMate2.

Storage

  • Anyone have more information on Jeda Networks? They’ve been mentioned a couple of times on GigaOm (here and here), but I haven’t seen anything concrete yet. Hey, Stephen Foskett, if you’re reading: get Jeda Networks to the next Tech Field Day.
  • Tim Patterson shares some code from Luc Dekens that helps check VMFS version and block sizes using PowerCLI. This could come in quite handy in making sure you know how your datastores are configured, especially if you are in the midst of a migration or have inherited an environment from someone else.

Virtualization

  • Interested in using SAML and Horizon Workspace with vCloud Director? Tom Fojta shows you how.
  • If you aren’t using vSphere Host Profiles, this write-up on the VMware SMB blog might convince you why you should and show you how to get started.
  • Michael Webster tackles the question: is now the best time to upgrade to vSphere 5.1? Read the full post to see what Michael has to say about it.
  • Duncan points out an easy error to make when working with vSphere HA heartbeat datastores in this post. Key takeaway: sometimes the fix is a lot simpler than we might think at first. (I know I’m guilty of making things more complicated than they need to be at times. Aren’t we all?)
  • Jon Benedict (aka “Captain KVM”) shares a script he wrote to help provide high availability for RHEV-M.
  • Chris Wahl has a nice write-up on using log shipping to protect your vCenter database. It’s a bit over a year old (surprised I missed it until now), and—as Chris points out—log shipping doesn’t protect the database (primary and secondary copies) against corruption. However, it’s better than nothing (which I suspect it what far too many people are using).

Other

  • If you aspire to be a writer—whether that be a blogger, author, journalist, or other—you might find this article on using the DASH method for writing to be helpful. The six tips at the end of the article are especially helpful, I think.

Time to wrap this up for now; the rest will have to wait until the next Technology Short Take. Until then, feel free to share your thoughts, questions, or rants in the comments below. Courteous comments are always welcome!

Technology Short Take #26

Welcome to Technology Short Take #26! As you might already know, the Technology Short Takes are my irregularly-published collections of links, articles, thoughts, and (sometimes) rants. I hope you find something useful here!

Networking

  • Chris Colotti, as part of a changed focus in his role at VMware, has been working extensively with Nicira NVP. He’s had a couple of good posts; this one is a primer on how NVP works, and this one discusses the use of the Open vSwitch (OVS) vApp. As I mentioned before in other posts, OVS is popping up in more and more places—it might be a good idea to make sure you’re familiar with it.
  • This article by Ivan Pepelnjak on VXLAN termination on physical devices is over a year old, but still very applicable—especially considering Arista Networks recently announced their 7150S switch, which sports hardware VTEP (VXLAN Tunnel End Point) support (meaning that it can terminate VXLAN segments).
  • Brad Hedlund dives into Midokura Midonet in this post on L2-L4 network virtualization. It’s a good overview (thanks Brad!) and worth reading if you want to get up to speed on what Midokura is doing. (Oh, just as an aside: note that Midokura leverages OVS in their solution. Just saying…)
  • This blog post provides more useful information from Kamau Wanguhu on VXLAN and proxy ARP. Kamau also has an interesting post on network virtualization, although—to be honest—the post is long on messaging/positioning and short on technical information. I prefer the latter instead of the former.

Servers/Hardware

  • This mention of the Dell PowerEdge M I/O Aggregator looks interesting, although I’m still not real clear on exactly what it is or how it works. I guess this first article was a tease?

Security

Nothing this time around, but I’ll stay alert for items to include in future posts!

Cloud Computing/Cloud Management

  • Want to know a bit more about how to configure VXLAN inside VCD? Rawlinson Rivera has a nice write-up that is worth reviewing.
  • Clint Kitson, an EMC vSpecialist, talks about some VCD integrity scripts he created. Looks like some pretty cool stuff—great work, Clint!
  • For the past couple of weeks I’ve been (slowly) reading Kevin Jackson’s OpenStack Cloud Computing Cookbook; it’s very useful. It’s worth a read if you want to get up to speed on OpenStack; naturally, you can get it from Amazon.

Operating Systems/Applications

  • At the intersection of cloud-based storage and configuration management, I happened to find this very interesting Puppet module designed to fetch and update files from an S3 bucket. Through this module, you could store files in S3 instead of using Puppet’s built-in file server. (By the way, this module also works with OpenStack Swift as well.)
  • One of the things I’ve complained about regarding newer versions of OS X is the “hiding” of the Unix underpinnings. Perhaps I should read this book and see if my thinking is unfounded?

Storage

  • Chris Evans takes a look at Hyper-V 3.0′s Virtual Fibre Channel feature in this write-up. From what I’ve read, it sounds like Hyper-V’s NPIV implementation is more robust than VMware’s broken and busted NPIV implementation. (If you don’t know why I say that about VMware’s implementation, ask anyone who’s tried to use it.) The real question is this: is NPIV support in a hypervisor of any value any longer?
  • Gina Minks (formerly of Dell, now with Inktank) recommended I have a look at Ceph and mentioned this post on migrating to Ceph (with a little libvirt thrown in).
  • Gluster might be another project that I need to spend some time examining; this post on using Gluster with oVirt 3.1 looks interesting. Anyone have any pointers for a Gluster beginner?
  • Mirantis has a post about some Nova Volume integration with Isilon. I’ve often said that I think scale-out platforms like Isilon (among others) are an important foundation for future storage solutions. It’s cool to see some third-party development happening to integrate Isilon and OpenStack.

Virtualization

That’s all for this time around. As always, courteous comments are welcome (encouraged, in fact!), so feel free to speak up in the comments below. I’d love to hear your feedback.

Technology Short Take #25

Welcome to Technology Short Take #25, my irregularly-published collection of links, articles, thoughts, and rants. It’s been a while since my last Technology Short Take (almost three months!); my apologies for that. This is my first time publishing a Technology Short Take with my new filesystem-based approach of managing resources. We’ll see how well it goes…

In any case, let’s get on with it!

Networking

  • Some folks from Nicira (now part of VMware) recently published a blog post discussing the OVSDB IETF draft (see here). It’s a valid point—people get all worked up over OpenFlow, but OpenFlow doesn’t address the management plane (only the control plane). Unfortunately, the management plane is often the place where vendors choose to “innovate” and “differentiate” their offerings, which—in my humble view—makes any sort of standardization in the management plane extremely difficult. I could be wrong (wouldn’t be the first time).
  • I think this three-part series on new network models for cloud computing (part 1, part 2, and part 3), while almost a year old, is quite good. James Urquhart, the author of the series, does a good job of breaking down some of the commonly-discussed “disruptive” technologies like Quantum (part of OpenStack) and OpenFlow. Worth a read if you are trying to get up to speed on these efforts, in my opinion.
  • There’s some additional information on the Quantum release on Folsom here.
  • Erik Smith, notably known for his outstanding posts on storage and FCoE, takes a stab at describing some of the differences between SDN and network virtualization in this post.
  • I found this series of posts to be helpful when I was working on configuring LACP with Open vSwitch (I hope to have a blog post on that up soon).
  • Reading these early OpenFlow meeting notes (via Brent Salisbury, aka @networkstatic on Twitter) was very fascinating. There’s a lot to digest there (for me, anyway, there is a lot to digest).

Servers/Hardware

Nothing this time around—but I’ll keep my eyes peeled for interesting information to include next time!

Security

  • I came across this post on CloudFoundry’s User Account and Authentication Service (the UAA). If you’re seeking more information on UAA, this looks like a good place to start.

Cloud Computing/Cloud Management

Operating Systems/Applications

  • I haven’t had much time to spend working with Puppet (a shame, I really enjoy the product—hopefully I’ll get back to it soon). When I do get back into working with Puppet again, I’m going to do my best to follow this advice regarding Puppet modules.

Storage

  • Sean Thulin has a nice write-up on configuring VASA for use with a VNX.
  • Is Cisco’s Insieme effort producing a storage product? Some interesting speculation can be found here and here (hat tip to Erik Smith).
  • Speaking of Erik Smith…this post on the impact of bit errors on I/O consolidation is a great post. I learn something from just about every one of Erik’s posts.
  • Another great post by Jason Boche on thin provisioning and VAAI UNMAP support. He does a great job of pulling together resources and explaining how it all works, including some great practical advice for real-world usage.
  • If storage is your thing—especially in VMware environments—I’d recommend having a look at Cormac Hogan’s blog for his series on vSphere 5.1 storage enhancements. It starts here.
  • There’s an interesting write-up here on a globally distributed OpenStack Swift cluster. What wasn’t clear to me—I guess I’m just dense—was whether the functionality SwiftStack was describing in their post was actually in current releases of Swift (and, if so, is it only in their commercial Swift release, or the open source Swift versions) or if this was “pie-in-the-sky” thinking about functionality that should be added at some point in the future. Anyone have any clarification here?

Virtualization

  • Need to add an alias to your vCloud Director cell? Jason Boche shows you how.
  • This is kind of a nice feature in Hyper-V 3: DHCP Guard. According to this article by Rick Vanover, this feature allows you to protect your network against rogue/unauthorized DHCP servers. Anyone actually tried this feature out yet (other than in a lab)?
  • William Lam shows you how to use ovftool to copy VMs directly between ESXi hosts. That’s pretty handy.
  • Only a true geek would be interested in this, but here’s some information on running OpenBSD in KVM on Linux. Given my past interest in OpenBSD and my present interest in KVM on Linux, this might be something I’ll be trying myself soon. Sadly, it looks like that post is the author’s last post in three years…shame.
  • I’m not sure if this should be considered “storage” or “virtualization,” as the lines continue to blur every day. In any case, this article by Frank Denneman on Storage DRS load balancing frequency might be useful to you.
  • This post describes some of the benefits of KVM’s VirtIO driver and how to use VirtIO with OpenStack. You’ll note, by the way, that Nova uses libvirt to manipulate KVM. This is one of the reasons I’ve been spending some time with libvirt—as part of the “glue” between Nova and KVM, I think it’s important to understand how libvirt works. (This is also why I’ve been spending time with Open vSwitch, which is a critical construct in Quantum.)

I suppose I should wrap things up now. Feel free to speak up in the comments if you found something I included here useful, or if there’s additional information that would benefit other readers. All courteous comments are welcome!

Technology Short Take #23

Welcome to Technology Short Take #23, another collection of links and thoughts related to data center technologies like networking, storage, security, cloud computing, and virtualization. As usual, we have a fairly wide-ranging collection of items this time around. Enjoy!

Networking

  • A couple of days ago I learned that there are a couple open source implementations of LISP (Locator/ID Separation Protocol). There’s OpenLISP, which runs on FreeBSD, and there’s also a project called LISPmob that brings LISP to Linux. From what I can tell, LISPmob appears to be a bit more focused on the endpoint than OpenLISP.
  • In an earlier post on STT, I mentioned that STT’s re-use of the TCP header structure could cause problems with intermediate devices. It looks like someone has figured out how to allow STT through a Cisco ASA firewall; the configuration is here.
  • Jose Barreto posted a nice breakdown of SMB Multichannel, a bandwidth-enhancing feature of SMB 3.0 that will be included in Windows Server 2012. It is, unexpectedly, only supported between two SMB 3.0-capable endpoints (which, at this time, means two Windows Server 2012 hosts). Hopefully additional vendors will adopt SMB 3.0 as a network storage protocol. Just don’t call it CIFS!
  • Reading this article, you might deduce that Ivan really likes overlay/tunneling protocols. I am, of course, far from a networking expert, but I do have to ask: at what point does it become necessary (if ever) to move some of the intelligence “deeper” into the stack? Networking experts everywhere advocate the “complex edge-simple core” design, but does it ever make sense to move certain parts of the edge’s complexity into the core? Do we hamper innovation by insisting that the core always remain simple? As I said, I’m not an expert, so perhaps these are stupid questions.
  • Massimo Re Ferre posted a good article on a typical VXLAN use case. Read this if you’re looking for a more concrete example of how VXLAN could be used in a typical enterprise data center.
  • Bruce Davie of Nicira helps explain the difference between VPNs and network virtualization; this is a nice companion article to his colleague’s post (which Bruce helped to author) on the difference between network virtualization and software-defined networking (SDN).
  • The folks at Nicira also collaborated on this post regarding software overhead of tunneling. The results clearly favor STT (which was designed to take advantage of NIC offloading) over GRE, but the authors do admit that as “GRE awareness” is added to the cards that protocol’s performance will improve.
  • Oh, and while we’re on the topic of SDN…you might have noticed that VMware has taken to using the term “software-defined” to describe many of the services that vSphere (and related products) provide. This includes the use of software-defined networking (SDN) to describe the functionality of vSwitches, distributed vSwitches, vShield, and other features. Personally, I think that the term software-based networking (SBN) is far more applicable than SDN to what VMware does. It is just me?
  • Brad Hedlund wrote this post a few months ago, but I’m just now getting around to commenting about it. The gist of the article—forgive me if I munge it too much, Brad—is that the use of open source software components might dramatically change the shape/way/means in which networking protocols and standards are created and utilized. If two components are communicating over the network via open source components, is some sort of networking standard needed to avoid being “proprietary”? It’s an interesting thought, and goes to show the power of open source on the IT industry. Great post, Brad.
  • One more mention of OpenFlow/SDN: it’s great technology (and I’m excited about the possibilities that it creates), but it’s not a silver bullet for scalability.

Security

  • I came across this interesting post on a security attack based on VMDKs. It’s quite an interesting read, even if the probability of being able to actually leverage this attack vector is fairly low (as I understand it).

Storage

  • Chris Wahl has a good series on NFS with VMware vSphere. You can catch the start of the series here. One comment on the testing he performs in the “Same Subnet” article: if I’m not mistaken, I believe the VMkernel selection is based upon which VMkernel interface is listed in the first routing table entry for the subnet. This is something about which I wrote back in 2008, but I’m glad to see Chris bringing it to light again.
  • George Crump published this article on using DCB to enhance iSCSI. (Note: The article is quite favorable to Dell, and George discloses an affiliation with Dell at the end of the article.) One thing I did want to point out is that—if I recall correctly—the 802.1Qbb standard for Priority Flow Control only defines a single “no drop” class of service (CoS). Normally that CoS is assigned to FCoE traffic, but in an environment without FCoE you could assign it to iSCSI. In an environment with both, that could be a potential problem, as I see it. Feel free to correct me in the comments if my understanding is incorrect.
  • Microsoft is introducing data deduplication in Windows Server 2012, and here is a good post providing an introduction to Microsoft’s deduplication implementation.
  • SANRAD VXL looks interesting—anyone have any experience with it? Or more detailed technical information?
  • I really enjoyed Scott Drummonds’ recent storage performance analysis post. He goes pretty deep into some storage concepts and provides real-world, relevant information and recommendations. Good stuff.

Cloud Computing/Cloud Management

  • After moving CloudStack to the Apache Software Foundation, Citrix published this discourse on “open washing” and provides a set of questions to determine the “openness” of software projects with which you may become involved. While the article is clearly structured to favor Citrix and CloudStack, the underlying point—to understand exactly what “open source” means to your vendors—is valid and worth consideration.
  • Per the AWS blog, you can now export EC2 instances out of Amazon and into another environment, including VMware, Hyper-V, and Xen environments. I guess this kind of puts a dent in the whole “Hotel California” marketing play that some vendors have been using to describe Amazon.
  • Unless you’ve been hiding under a rock for the past few weeks, you’ve most likely heard about Nick Weaver’s Razor project. (If you haven’t heard about it, here’s Nick’s blog post on it.) To help with the adoption/use of Razor, Nick also recently announced an overview of the Razor API.

Virtualization

  • Frank Denneman continues to do a great job writing solid technical articles. The latest article to catch my eye (and I’m sure that I missed some) was this post on combining affinity rule types.
  • This is an interesting post on a vSphere 5 networking bug affecting iSCSI that was fixed in vSphere 5.0 Update 1.
  • Make a note of this VMware KB article regarding UDP traffic on Linux guests using VMXNET3; the workaround today is using E1000 instead.
  • This post is actually over a year old, but I just came across it: Luc Dekens posted a PowerCLI script that allows a user to find the maximum IOPS values over the last 5 minutes for a number of VMs. That’s handy. (BTW, I have fixed the error that kept me from seeing the post when it was first published—I’ve now subscribed to Luc’s blog.)
  • Want to use a Debian server to provide NFS for your VMware environment? Here is some information that might prove helpful.
  • Jeremy Waldrop of Varrow provides some information on creating a custom installation ISO for ESXi 5, Nexus 1000V, and PowerPath/VE. Cool!
  • Cormac Hogan continues to pump out some very useful storage-focused articles on the official VMware vSphere blog. For example, both the VMFS locking article and the article on extending an EagerZeroedThick disk were great posts. I sincerely hope that Cormac keeps up the great work.
  • Thanks to this Project Kronos page, I’ve been able to successfully set up XCP on Ubuntu Server 12.04 LTS. Here’s hoping it gets easier in future releases.
  • Chris Colotti takes on some vCloud Director “challenges”, mostly surrounding vShield Edge and vCloud Director’s reliance on vShield Edge for specific networking configurations. While I do agree with many of Chris’ points, I personally would disagree that using vSphere HA to protect vShield Edge is an acceptable configuration. I was also unable to find any articles that describe how to use vSphere FT to protect the deployed vShield appliances. Can anyone point out one or more of those articles? (Put them in the comments.)
  • Want to use Puppet to automate the deployment of vCenter Server? See here.

I guess it’s time to wrap up now, lest my “short take” get even longer than it already is! Thanks for reading this far, and I hope that I’ve shared something useful with you. Feel free to speak up in the comments if you have questions, thoughts, or clarifications.

Technology Short Take #19

Welcome to Technology Short Take #19, the first Technology Short Take for 2012. Here’s this year’s first collection of links, articles, and thoughts regarding virtualization, storage, networking, and other data center technology-related topics. I hope you find something useful!

Networking

  • While configuration limits aren’t the most exciting reading, they are important from time to time. Here’s some configuration limits for the UCS 6100 and 6200 series.
  • Understanding the differences—both positive and negative—between the various approaches to solving a particular challenge is a key skill. That’s why I like this article on HP Flex-10 versus NIOC for VDI. The author (Dwayne) weighs the pros and cons of both approaches in helping to shape network traffic for VDI deployments using 10Gb Ethernet.
  • It would appear that my recent VXLAN and OTV connectivity posts (incorrect VXLAN post here, corrected VXLAN post here, and OTV/VXLAN post here) sparked a discussion about whether we really need to concern ourselves with traffic trombones. On one side we have Brad Hedlund speculating that the network should be treated like a large virtual I/O fabric; on the other side we have Greg Ferro countering that we do need to be concerned about the topology of the network. I can see both sides of the argument, but at this stage of the game, I’m inclined to agree more with Greg. In the future (it’s unclear how far in the future) I think that Brad’s points will be more valid, but not right now.
  • This post by Ivan Pepelnjak on VXLAN, IP multicast, OpenFlow, and control planes highlights some of the current limitations with VXLAN and thus reinforces why I think that Brad’s arguments are a bit ahead of their time.
  • A few folks had some write-ups on Embrane Heleos: Greg Ferro, Jason Edelman, Brad Hedlund, Brad Casemore, and Ivan Pepelnjak. My question (and this is spurred in part by some comments by Brad Casemore): is this another Cisco spin-in move?

Servers/Operating Systems/Applications

Storage

Virtualization

And that it’s for this time around; as always, I hope you’ve found something useful here. Courteous comments are always welcome; feel free to speak up below.

Technology Short Take #18

Welcome to Technology Short Take #18! I hope you find something useful in this collection of networking, OS, storage, and virtualization links. Enjoy!

Networking

The number of articles in my “Networking” bucket continues to overflow; I have so many articles on so many topics (soft switching, OpenFlow, Open vSwitch, MPLS) that it’s hard to get my head wrapped around all of it. Here are a few posts that stuck out to me:

  • Ivan Pepelnjak has a very well-written post explaining the various ways that virtual networking can be decoupled from the physical network.
  • I stumbled across a trio of articles by Denton Gentry on hash tables (part 1, part 2, and part 3). This is an interesting perspective I hadn’t considered before; as we move more into software-defined networks (SDNs), why are we continuing to use the same mechanisms as before? Why not take advantage of more efficient mechanisms as part of this transition?

Servers/Operating Systems

  • Nigel Poulton and I traded a few tweets during HP Discover Vienna about SCSI Express (or SCSI over PCIe, SoP). He wrote up his thoughts about SoP and its future in the storage industry here. Further Twitter-based discussions about fabrics led him to say that HP buying Xsigo would bring the competition back against UCS. I’m not so sure I agree. Xsigo’s server fabric technology/product is interesting, but it seems to me that it’s still adding layers of abstraction that aren’t necessary. As SR-IOV, MR-IOV, and PCIe extension matures, it seems to me that Ethernet as the fabric is going to win. If that’s the case, and HP wants to bring the hurt against UCS, they’re going to have to invest in Ethernet-based fabrics.
  • Speaking of UCS, here’s a “how to” on deploying the UCS Platform Emulator on vSphere. You might also like the UCS PE configuration follow-up post.
  • Here’s what looks to be a handy Mac OS X utility to track how long until your Active Directory password expires. Sounds simple, yes, but useful.

Storage

Virtualization

  • Jason Boche, after some collaboration with Bob Plankers, wrote up a good procedure for expanding the vCloud Director Transfer Server storage space. It’s definitely worth a read if you’re going to be working with vCloud Director.
  • Microsoft has released version 3.2 of the Linux Integration Services for Hyper-V. The new release adds integrated mouse support, updated network drivers, and fixes an issue with SCVMM compatibility.
  • Julian Wood, who I had the opportunity to meet in Copenhagen at VMworld 2011, has published a four-part series on managing vSphere 5 certificates. Follow these links for the series: part 1, part 2, part 3, and part 4.
  • Thinking of deploying Oracle on vSphere? You should probably read this three-part series from VMware’s Business Critical Applications blog: part 1 is here, part 2 is here, and part 3 is here.
  • I’m so used to dealing with VLANs in a vSphere environment, I didn’t consider the challenges that might come up when using them with VMware Workstation. Fortunately, this author did—read his post on mapping VLANs to VMnets in VMware Workstation.
  • I thought that this article on virtual disks with business critical applications would be a deep dive on which virtual disk formats (thin, lazy zeroed, eager zeroed) are best suited for various applications. While the article does discuss the different virtual disk formats, unfortunately that’s as far as it goes.
  • Fellow VMware vSphere Design co-author Forbes Guthrie highlights an important design concern with AutoDeploy: what about a virtual vCenter instance? Read his full article for the in-depth discussion.
  • This post by William Lam gives a good overview of when vSphere MoRefs change (or don’t change).
  • Here’s a good explanation why NIC teaming can’t be used with iSCSI binding.
  • Cormac Hogan also posted a nice overview of some new vmkfstools enhancements in vSphere 5.
  • Terence Luk posts a detailed procedure to help recover VMware Site Recovery Manager in the event of a failure of one of the SRM servers. Good information—thanks Terence!

And that’s it for this time around. Feel free to add your thoughts in the comments below—all comments are welcome! (Please provide full disclosure of vendor affiliations/employment where applicable. Thanks!)

Examining VXLAN

It’s taken me far too long to write this post, that’s for sure. Since the announcement of VXLAN at VMworld earlier in the year, I’ve been searching for additional information on these questions: “What is VXLAN? How does it fit into the broader networking landscape? Why did we need a new standard?” I talked to Cisco, I attended a VMworld session about networking futures, I talked to some of the authors of the IETF draft on VXLAN, I read (most of) the VXLAN draft, and I studied some existing protocols that one might think could have been put to use. I think I’m finally ready to try to address these questions.

What is VXLAN?

The answer to this question is taken directly from the IETF draft (the emphasis is mine):

This document describes Virtual eXtensible Local Area Network (VXLAN), which is used to address the need for overlay networks within virtualized data centers accommodating multiple tenants.

I think it’s important to keep this purpose in mind. While it’s a bit simplistic to state it this way, VXLAN is—essentially—a proposed standards-based replacement for the proprietary MAC-in-MAC encapsulation that is currently used in vCloud Director. Instead of using MAC-in-MAC encapsulation, VXLAN uses MAC-in-IP encapsulation, with multicast groups to handle MAC learning and unique UDP source ports to help with load balancing across multiple links. Yes, that’s a bit of a simplification, but I think it gets the main point across.

How does VXLAN fit into the broader networking landscape?

Trying to answer this question is what has occupied the majority of the time it’s taken to write this post. You can’t explain how VXLAN fits into the broader networking landscape without having a minimal understanding, at least, of what the rest of the networking landscape looks like. I had to dig in a bit deeper to MPLS, OTV, FabricPath/TRILL, and other standards/emerging standards. I’m sure that I’ve still omitted some technologies that should have been included, and I know that there are still (so much) more to learn about the technologies I did include.

Based on the information I was able to gather, the answer to this second question really builds on the answer to the first question. VXLAN only really addresses a few fundamental concerns:

  • A shortage of VLAN address space (the theoretical limit is 4094 VLANs, with many switches supporting fewer than that)
  • An inability to support multi-tenancy (both from a scale perspective as well as a separation perspective)
  • Problems with Layer 2 connectivity across disparate virtual data centers

VXLAN addresses these concerns in this way:

  • It adds a 24-bit VXLAN Network Identifier (VNI), expanding the realm of potentially unique identifiers to just shy of 17 million (16.7 million). This addresses any scale-based concerns of multitenancy.
  • It wraps Layer 2 frames in Layer 3 packets. This addresses the other part of any multitenancy concerns (VXLAN hides duplicate MAC addresses, duplicate IP addresses, and duplicate VLAN IDs found in separate VNIs). This also addresses the Layer 2 connectivity issues between disparate virtual data centers.

And that’s really about it. It doesn’t address Layer 2 multipathing/STP, it doesn’t address Layer 2 connectivity in the physical world (layer 2 connectivity is only preserved at the virtualization level), and it doesn’t address Layer 3 routing issues created by stretched VLANs and VM mobility designs. Which brings us to our third question…

Why did we need a new standard?

This answer builds on the previous two answers. Once you have a clear understanding of what VXLAN was designed to do, and how VXLAN fits into the rest of the networking protocols, then this answer is pretty easy:

  • If you’ve been reading my articles, you know already that VXLAN doesn’t preserve all forms of Layer 3 connectivity. Because it doesn’t, you still need protocols like OTV to address Layer 2/3 connectivity at the physical level.
  • Because you still need protocols like OTV to achieve VM mobility (for the time being, at least), you’re still going to need protocols like LISP to fix funny routing issues being caused by IP addresses from the same subnet existing in multiple locations at the same time.
  • Because VXLAN doesn’t address Layer 2 multipathing concerns, you still need protocols like TRILL and technologies like FabricPath.
  • Because using MPLS—which, by the way, would also address the 3 concerns VXLAN addresses—would require MPLS-enabled/MPLS-aware equipment throughout the data center, that would make an MPLS-based solution difficult for many enterprises to adopt. Using an IP encapsulation scheme means that existing physical networking equipment doesn’t have to change. (Although it might change—to add VXLAN support—at some point in the future.)

I was not a fan of VMware (apparently) driving the creation of an entirely new networking standard. However, as I dug into this, I began to see that while other solutions almost addressed these concerns, none of them were a really good fit. Yes, using MPLS probably would have worked. Using GRE might have worked (take NVGRE, for example, but that’s also a proposed new protocol). To really address the concerns head-on, though, required a solution that was written/created expressly for that purpose, and that’s VXLAN. It’s just important, though, to really understand what VXLAN is as well as what VXLAN isn’t. Otherwise, you’ll find yourself trying to fit VXLAN to a solution for which it really wasn’t intended—which, by the way, was why VXLAN was created in the first place.

Comments, corrections, and clarifications are always welcome!

Technology Short Take #17

Welcome to Technology Short Take #17, another of my irregularly-scheduled collections of various data center technology-related links, thoughts, and comments. Here’s hoping you find something useful!

Networking

  • I think it was J Metz of Cisco that posted this to Twitter, but this is a good reference to the various 10 Gigabit Ethernet modules.
  • I’ve spoken quite a bit about stretched clusters and their potential benefits. For an opposing view—especially regarding the use of stretched clusters as a disaster avoidance solution—check out this article. It’s a nice counterpoint, especially from the perspective of the network.
  • Anyone know anything about sFlow?
  • Here’s a good post on VXLAN that has some useful information. I’d just like to point out that VXLAN is really only intended to address Layer 2 communications “within” a vApp or a collection of VMs (perhaps a single organization’s VMs), and doesn’t do anything to address Layer 3 routing/accessibility for clients (or “consumers”) attempting to connect to those systems. For that, you’ll still need—at least today—technologies like OTV, LISP, and others.
  • A quick thought that I’m still exploring: what’s the impact of OpenFlow on technologies like VXLAN, NVGRE, and others? Does SDN eliminate the need for these technologies? I’d be curious to hear your thoughts.

Servers/Operating Systems

  • If you’ve adopted Mac OS X Lion 10.7, you might have noticed some problems connecting to older servers/NAS devices running AFP (AppleTalk Filing Protocol). This Apple KB article describes a fix. Although I’m running Snow Leopard now, I was running Lion on a new MacBook Pro and I can attest that this fix does work.
  • This Microsoft KB article describes how to extend the Windows Server 2008 evaluation period. I’ve found this useful for Windows Server 2008 instances in the lab that I need for longer 60 days but that I don’t necessarily want to activate (because they are transient).

Storage

  • Jason Boche blogged about a way to remove stubborn hosts from Unisphere. I’ve personally never seen this problem, but it’s nice to know how to address it should it occur.
  • Who would’ve thought that an HDD could serve as a cache for an SSD? Shouldn’t it be the other way around? Normally, that would probably be the case, but as described here there are certain instances and ways in which using an HDD as a cache for an SSD can improve performance.
  • Scott Drummonds wraps up his 3 part series on flash storage in part 3, which contains information on sizing flash storage. If you haven’t been reading this series, I’d recommend giving it a look.
  • Scott also weighs in on the flash as SSD vs. flash on PCIe discussion. I’d have to agree that interfaces are important, and the ability of the industry to successfully leverage flash on the PCIe bus is (today) fairly limited.
  • Henri updated his VNXe blog series with a new post on EFD and RR performance. No real surprises here, although I do have one question for Henri: is that your car in the blog header?

Virtualization

  • Interested in setting up host-only networking on VMware Fusion 4? Here’s a quick guide.
  • Kenneth Bell offers up some quick guidelines on when to deploy MCS versus PVS in a XenDesktop environment. MCS vs. PVS is a topic of some discussion on the vSpecialist mailing list as they have very different IOPs requirements and I/O profiles.
  • Speaking of VDI, Andre Leibovici has two articles that I wanted to point out. First, Andre does a deep dive on Video RAM in VMware View 5 with 3D; this has tons of good information that is useful for a VDI architect. (The note about the extra .VSWP overhead, for example, is priceless.) Andre also has a good piece on VDI and Microsoft Outlook that’s worth reading, laying out the various options for Outlook-related storage. If you want to be good at VDI, Andre is definitely a great resource to follow.
  • Running Linux in your VMware vSphere environment? If you haven’t already, check out Bob Plankers’ Linux Virtual Machine Tuning Guide for some useful tips on tuning Linux in a VM.
  • Seen this page?
  • You’ve probably already heard about Nick Weaver’s new “Uber” tool, a new VM alignment tool called UBERAlign. This tool is designed to address VM alignment, a problem with how guest file systems are formatted within a VMDK. For more information, see Nick’s announcement here.
  • Don’t disable DRS when you’re using vCloud Director. It’s as simple as that. (If you want to know why, read Chris Colotti’s post.)
  • Here’s a couple of great diagrams by Hany Michael on vCloud Director management pods (both public cloud and private cloud management).
  • People automatically assume that “virtualization” means consolidating multiple workloads onto a single physical server. However, virtualization is really just a layer of abstraction, and that layer of abstraction can be used in a variety of ways. I spoke about this in early 2010. This article (written back in March of 2011) by Brad Hedlund picks up on that theme to show another way that virtualization—or, as he calls it, “inverse virtualization”—can be applied to today’s data centers and today’s applications.
  • My discussion on the end of the infrastructure engineer generated some conversations, which is good. One of the responses was by Aaron Sweemer in which he discusses the new (but not new) “data layer” and expresses a need for infrastructure engineers to be aware of this data layer. I’d agree with a general need for all infrastructure engineers to be aware of the layers above them in the stack; I’m just not convinced that we all need to become application developers.
  • Here’s a great post by William Lam on the missing piece to creating your own vSEL cloud. I’ll tell you, William blogs some of the coolest stuff…I wish I could dig in as deep as he does in some of this stuff.
  • Here’s a nice look at the use of PowerCLI to help with the automation of DRS rules.
  • One of my projects for the upcoming year is becoming more knowledgeable and conversant with the open source Xen hypervisor and Citrix XenServer. I think that the XenServer Design Handbook is going to be a useful resource for that project.
  • Interested in more information on deploying Oracle databases on vSphere? Michael Webster, aka @vcdxnz001 on Twitter, has a lengthy article with lots of information regarding Oracle on vSphere.
  • This VMware KB article describes how to enable centralized logging for vCloud Director cells. This is particularly important for HA environments, where VMware’s recommended HA strategy involves the use of multiple vCD cells.

I guess I should wrap it up here, before this post gets any longer. Thanks for reading this far, and feel free to speak up in the comments!

Technology Short Take #16

Welcome to Technology Short Take #16. It’s been quite a while since my last Technology Short Take (a month!), and I don’t know if that’s a good thing (so readers didn’t have to listen to my rambling) or a bad thing (readers missing out on what I hope are useful or interesting links). In any case, here’s my latest collection of various data center-related links, articles, and thoughts. Thanks for reading!

Networking

  • A great of my networking-related reading over the last few weeks has been focused on OpenFlow and trying to better understand what it is and how it affects things (both today and in the future). I won’t share all of them here (I’ll probably post a separate collection of all the links I’ve gathered), but I did want to mention that briefly. Of particular interest to me is the interaction/integration between OpenFlow, Open vSwitch, and OpenStack. Any notes/thoughts/ideas there that readers would like to share are welcomed.
  • While this post on NVGRE, VXLAN, and what Microsoft is doing right is a bit slanted in favor of Open vSwitch, I do agree that standardizing the control plane for managing the virtual networking platform is a worthy goal. We all know, intuitively, that we need better orchestration and more extensive automation; providing a standardized control interface is one step closer to achieving that, in my opinion.
  • Ivan has a great treatise on why virtual switches need BPDU guard. As usual, his post is spot on—with one minor exception. Current recommendations for vSphere HA state that, in most cases, isolation response should be configured to leave VMs powered on. Thus, the scenario he describes in which a misconfigured VM might take down all the links on an ESX/ESXi host and then cause the VMs to be rebooted is far less likely to occur. Even so, that’s a minor nit, and the point of the article remains valid and useful.

Servers

  • For a bit of a real-world look at Cisco UCS, read this post by Chris Atkinson, a fairly recent adopter of UCS in his environment.

Storage

  • If you haven’t had a chance to catch up with Rob Peglar’s “Architecture Matters” series of blog posts, I think it’s worth checking out. Part 1 is here and part 2 is here. (Rob, by the way, is the Americas CTO for Isilon.)
  • The “readiness” of FCoE for the enterprise is a topic that has come up once again. Stephen Foskett stirred the waters—something that he seems to be doing more frequently now—with this article. Predictably (and I don’t mean that in a bad way), J Metz has come out squarely on the side of “FCoE is ready” (read his post); Greg Ferro has come out swinging against FCoE (read his post). I can see both sides of the argument; personally, I think that these two sides are operating on different measurements. J Metz is working from the perspective of standards readiness and product availability; Stephen and Greg are working from the perspective of market adoption. Neither is a good indicator alone of enterprise readiness; rather, both need to be taken together.
  • Interested in a bit more detail on how VNX volumes work? Check out this article by Joe Kelly of Varrow.
  • Scott Drummonds has a great series going on titled “The Flash Storage Revolution”. In part 1, Scott discussed why flash is so important in enterprise storage today; in part 2, Scott addressed the factors that companies must consider when deciding how to best use flash in their environments. I’m looking forward to part 3!
  • Brandon Riley has a good couple of posts showing some differences between PowerPath/VE and Round Robin on VMAX (part 1 and part 2). The differences with “out of the box” settings are quite dramatic in favor of PowerPath/VE; with some tuning, Round Robin pulls in much closer. Of course, raw performance is important, but failure behaviors are also important; it would be great if Brandon could incorporate some failure scenario behaviors into his scorecard.
  • Jeramiah Dooley of VCE has a good article examining the value of FAST VP and FAST Cache for service providers. It’s a good read that I’d recommend.

Virtualization

  • It seems that writing a series of articles is all the rage these days; Chris Colotti has a series going titled “vCloud Director Clone Wars” that discusses the considerations around the use of vSphere clones in vCloud Director environments. Have a look at the series: part 1, part 2, and part 3.
  • Want to use PXE with VMs under VMware Fusion? This post shows you how.
  • Interested in running Hyper-V under ESXi 5? It’s possible; this VMware Communities document provides some information. I’d also recommend having a look here as well.
  • While we are on the top of nested VMs, William Lam wrote up how to install the VMware VSA in nested ESXi 5 host.
  • Here’s another article series, this time from Itzik Reich and addressing VMware SRM 5 with EMC Symmetrix (part 1 and part 2).
  • Cisco UCS VM-FEX is the subject of this 3-part series from Joe Keegan at Infrastructure Adventures (part 1, part 2, and part 3).
  • More nesting madness: running Virtual PC inside Hyper-V? Ben Armstrong discusses the need for MAC spoofing in that scenario.
  • Want an opportunity to win a $50 gift card? Go supply your VDI read/write IOPS data statistics over at Andre’s site.
  • It’s no secret that I’ve been discussing stretched clusters for quite some time (as far back as last September with this presentation, and then again here and here), so it’s great to see other people in the virtualization community talking about the subject as well. Duncan posted an article focusing on failure scenarios and Chad Sakac posted an article on the new stretched cluster HCL category. This December at the Brisbane and Melbourne VMUG events, I’ll be presenting some new content on stretched clusters, so stay tuned for that.

I guess it’s time to wrap up now. Thanks for reading, and feel free to share any useful or pertinent links in the comments below.

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