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!

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Technology Short Take #17

• A Collection of vCloud Director Links
• Technology Short Take #16
• Technology Short Take #14
• Technology Short Take #10
• Technology Short Take #18

<aside>I can see where this might be an area of some confusion; in fact, I was just discussing hyperthreading with a colleague last week. In my opinion, it’s far more accurate to refer to current-generation functionality as SMT than hyperthreading, but that’s another story for another day.</aside>

What really caught my eye was the part of the article where the author compares and contrasts Microsoft’s approach and others’ approaches. I’ve taken a screenshot here in case the original article changes. Keep in mind that the article is based on the discussion of maximum virtual CPUs (or VPs, as WSV_GUY calls them) per logical CPU:

Figure 1. Screenshot of Microsoft blog post

So, two things pop to mind immediately. Let’s take these in order.

First—since it’s fairly obvious that Microsoft is targeting VMware as the primary “other virtualization vendor”—it should be noted that VMware does not consistently use cores as their unit of measure. As a point of proof, I present to you this screenshot taken from VMware’s Configuration Maximums document for vSphere 4.1 (available in PDF here). I’ve taken the liberty of highlighting the two key takeaways:

Figure 2. Screenshot of VMware configuration maximums document

As you can see from the documentation, VMware inconsistently switches back and forth from logical CPUs to cores. From that perspective, VMware has some work to do on presenting consistent messaging and consistent documentation. Point taken. VMware, are you listening?

But that’s not really my major beef with the article.

The second thing I noted was the statement in the Microsoft blog (see Figure 1) about “Vendor A” and statements about ratios. Remember that the entire blog post appears to be about maximum ratios: “Vendor A response 16:1 (with the qualifier that your mileage will vary)”. It seems to me that the author is referring to the statement at the bottom of the VMware configuration maximums document (see Figure 2) that discusses the achievable number of virtual processors per core. However, we’re not talking about achievable ratios, we’re talking about maximum ratios, right? Or are we?

Although the Microsoft author appears to ding VMware for making a statement about achievable ratios in an article discussing maximum supported ratios, later in the same article the author does the same thing (the emphasis is mine):

You can see that even with an 8:1 VP to LP ratio (or 16:1 VP: Core, if you prefer), Hyper-V supports very dense VM configurations. Even on a server with two physical processors, Hyper-V supports a staggering number of virtual machines (up to 256). The limiting factor won’t be Hyper-V. It will be how much memory you’ve populated the server with and how well the storage subsystem performs.

Sounds to me like Microsoft is saying that they have a maximum ratio of virtual CPUs to logical CPUs, but that the actual ratio can you achieve (the achievable ratio?) might be less than that. How is that any different from the statement in VMware’s configuration maximums document? How is Microsoft’s “approach” with regard to ratios any different, better, or clearer for the customer? Yes, VMware’s documentation is inconsistent. But when it comes to maximum ratios vs. achievable ratios, it seems to me that the pot is calling the kettle black.

If I’m off or I’m overlooking something, please let me know by speaking up in the comments. Please use full disclosure of your employer where that employment might affect your viewpoint. Thanks!

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Is the Pot Calling the Kettle Black?

• VMware as Middleware
• Using Multiple VLANs with HP Virtual Connect Flex-10
• The vMotion Reality
• Virtualization Short Take #39
• Hyper-V Update Released

I am looking to design an ESXi environment to potentially deploy Microsoft SQL servers that require extreme high availability at a scale of 50+ MSCS/WFC clusters. We’d like to do this in an ESXi 4.1 environment using Windows Server 2008 R2, MSCS/WFC, and SQL Server 2008 with Fibre Channel storage. I’ve done this in the past on a smaller scale (3-4 total clusters) and know most of the caveats such as proper heartbeat requirements, no HA/DRS support, physical RDM compatibility mode requirements for shared disks, eageredzerothick OS disks, no round-robin multipathing, etc.

The issues I’ve run into in the past revolved around managing these virtual servers differently than other guests since they couldn’t readily be moved between hosts. We also found that the reboot time on these hosts with MSCS/WFC using RDMs was extremely slow (in excess of 45 minutes to fully reboot, we could speed this up by pulling the fibre cables).

Some of the design considerations I’m curious about would include:

• Where do people put the VMFS/RDM file links?
• Do people put the guests in different clusters? Is this even possible?
• How do people separate active/passive nodes? Do people use host based affinity rules to accomplish this?
• Do reboot times on hosts with lots of RDMs get linearly slower as more MSCS/WFC RDMs are presented to a host?
• Do people really push back and try to get database mirroring instead of clustering? If so, what caveats around this have people encountered?

I’m just curious how others are handling situations like this or if anyone is really doing it at scale.

Thoughts? What do you guys think about this reader’s situation? I’d love for this to jump start a conversation here with recommendations, experiences, additional questions, etc. vSphere design is a topic that lots of readers are tackling, either for certification or just because that’s their job, and the discussion around this scenario could end up exposing some useful resources and information.

So jump in with your thoughts in the comments below! I only ask that you provide full disclosure with regards to vendor affiliations, where applicable. Thanks, and I look forward to seeing some of the responses.

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Design Question from a Reader

• Distance vMotion = Stretched Cluster?
• Announcing VMware vSphere Design
• Determining an Optimal Design
• Giving Thanks on Thanksgiving
• Updated Stretched Cluster Presentation

• My son uses Mozilla Firefox (not Internet Explorer) with all updates installed.
• I keep Windows 7 patched with updates from Microsoft.
• He runs as a non-administrative user, and doesn’t know the administrator credentials.
• The Windows 7 firewall is enabled and configured with a fairly strict set of rules.
• The network has open source proxy server with content filters, so I can be reasonably confident he’s not visiting the really nasty sites. Obviously, content filters are never perfect and always in need to be updated, but they’re better than nothing.
• The network itself is protected by a hardware firewall (not a simple NAT router, but a true stateful firewall), which requires that all web traffic go through the proxy (so he can’t bypass the proxy).
• I installed Microsoft Security Essentials on his laptop to protect against malware, adware, etc., and I keep it updated.

Yet, despite all these layers of protection, I find that my son’s laptop was still infected with malware.

So I ask, in all seriousness—meaning I’m not trying to start some sort of flame war about how Mac OS X or Linux is better than Windows or vice versa—how does one protect their Windows installations against this sort of thing? I mean, what does it take, anyway? I feel like I am taking some pretty serious steps to protect Windows, and yet it still gets infected. What am I missing here?

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

What Does it Take to Keep Windows Secure?

• Windows 7, Microsoft Security Essentials, and Proxy Servers
• How Do Non-Geeks Fix Problems?
• Enough Bundling Already!
• HTTP Proxies and Command-Line Utilities
• Mac OS X Malware Uncovered

But enough of that for now; on with the content!

• Priority Flow Control (PFC) is an as-yet-unratified IEEE standard (IEEE 802.1Qbb) that is often linked closely to Fibre Channel over Ethernet (FCoE). If you’re interested in getting a bit more information on PFC and you’re not (yet) a networking expert, this introduction to 802.1Qbb is pretty handy.
• Didier Pironet recently documented some of vSphere 4.1′s advanced iSCSI settings. Good information, although what would be really handy was any recommendations around whether changing any of these settings should be considered and in what environments a change might be recommended. A future post, Didier?
• Ben Armstrong (aka “The Virtual PC Guy”) has posted two articles so far dealing with how to script Hyper-V’s dynamic memory. Part 1 shows how to read the dynamic memory configuration; part 2 shows how to display the current usage information. Ben also recently published an article on parent memory reserve, which is how Hyper-V reserves money for the parent partition running Windows Server 2008.
• This SearchTelecom.com article on Locator/ID Separation Protocol (LISP) gave me just the introduction I needed to LISP. After you read that article, you can continue your LISP education by visiting this brief blog post and checking out some of the other linked resources.
• I’ve written before about multi-hop FCoE (here and here, for example), but this post on multi-hop FCoE 101 is a great read and highlights some of the differences in vendor implementations. Based on the article, it’s these differences in vendor implementations that often lead to disagreements between the vendors with regard to what’s required or not required. (It seems like I’m really digging some of Ivan’s stuff recently. I’m going to have to add him to my list of networking RSS feeds!)
• Tried SLES 11 SP1 for VMware yet? Jase McCarty recently took it for a quick spin. Here are his thoughts.
• Jason Boche recently posted a fix for an error with vCenter Service Status in vCenter Server 4.1.
• For those readers who haven’t had the opportunity to work with Cisco’s Unified Compute System (UCS), there are lots of great bloggers out there writing about it—too many to name, in fact. Kevin Goodman captured a few of them in this list of Cisco UCS people and blogs. While you’re coming up to speed, though, this page from Cisco on upgrading the BIOS on a Cisco UCS server blade gives you an idea of how the system uses service profiles as the vehicle for almost everything. This similar post on Cisco’s web site breaks down the process of creating a service profile in UCS, a topic that I’ve tackled myself (with a four-part series that starts here).
• This page listing the Cisco UCS B-series network adapters shows some “Gen 2″-type cards, such as the M72KR-E Emulex CNA. Did I miss an announcement? Unlike the “Gen 1″ cards, the “Gen 2″ cards aren’t hyperlinked for more information.
• William Lam (@lamw on Twitter and elsewhere), whom I had the great pleasure of meeting personally last week while at VMworld 2010, has published what is likely to be the definitive primer on vsish, a largely undocumented utility. Check out the vsish write-up on William’s site. I also recently found an older article that William wrote on how to remove stale targets from vMA. vMA-related articles are almost like gold these days since all the geeks are needing a new command-line fix for ESXi.
• Working on a VDI environment and want to disable some of the welcome stuff that Windows throws your way? Check this out.

There were a few other links that I collected as well but didn’t really have anything to say about them; still, in the event they might prove useful, here they are:

Krystaltek: What ESX Admins Group? – A Tale of RTSM and AD
vCenter SRM Automatic Failback Options Using EMC Storage
Support Insider: VMware Snapshots
Running the VMware vSphere Hypervisor stateless
Best practice in LUN design (VMware Communities)
VMware KB: Using a VNC Client to Connect to Virtual Machines
VMware KB: Do I choose the PVSCSI or LSI Logic virtual adapter on ESX 4.0 for non-IO intensive workloads?
VMware ESXi 4.1 does not use whole disk capacity for VMFS3

That should do it this time around. Thanks for reading, and feel free to suggest additional articles or links that you think other readers would find useful.

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Technology Short Take #3

• Technology Short Take #4
• Technology Short Take #7
• Technology Short Take #12: Networking Edition
• Technology Short Take #16
• Technology Short Take #2

The install was quick and painless. And that’s where the fun started. MSE wanted to do an update immediately; OK, that’s fine. The problem is, it won’t connect. I use a Squid proxy server to control outbound web access, so I figured that somewhere was a setting that told MSE to use a proxy server. There’s nothing within MSE itself. Could it be that I had forgotten to configure Internet Explorer? I did make Firefox the default browser, after all. Nope, a quick check shows that the Internet Explorer settings are configured for the right outbound proxy as well. Both Internet Explorer and Firefox are working fine, so I know it’s not the network, the proxy, or the firewall. It must be MSE itself.

Google turns up the first part of the puzzle; even though your proxy support might be configured correctly for Internet Explorer (and thus most of the rest of Windows), MSE won’t take those settings. Instead, you have to use netsh, like this:

netsh winhttp import proxy source=ie

Unfortunately, in its efforts to be “helpful,” Windows 7 won’t allow you to run that command without elevated privileges. All you get when you try is a nondescript error message that vaguely implies that you don’t have permission. However, instead of being able to elevate that one command (a la sudo in the UNIX/Linux/BSD world), you have to run the entire command prompt with administrative privileges, like explained here (and probably countless other places on the ‘Net).

Once you get a command prompt running with administrative credentials, then you can run the netsh command and it will successfully import the IE proxy configuration. Once the IE proxy configuration is successfully imported, then MSE will fetch updates from the Internet and function properly. Wasn’t that fun?

This little episode brings up a couple questions/thoughts:

1. Why in the world wouldn’t MSE use IE’s proxy configuration? Most of the rest of Windows does.
2. Even if Microsoft wanted MSE to have its own proxy settings, why force users down a rathole of command prompts and administrative privileges? Why not put it in the GUI?
3. Windows 7 has made great strides in making Windows more secure, but does this enhanced security posture come at the price of decreased flexibility for the power user?
4. If so, does Microsoft even care? After all, the default settings are probably fine for most users.

Anyway, there you have it. If you use a proxy server on your network and you also want to use MSE, you’ll need to use netsh (with administrative privileges) to configure your proxy settings properly.

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Windows 7, Microsoft Security Essentials, and Proxy Servers

• What Does it Take to Keep Windows Secure?
• It’s Patch Tuesday Again
• New IE Flaws
• New Theme!
• WMF Flaw Exploit Grows Worse

It’s a interesting solution aimed squarely at the SMB market, where VMware has so far been relatively unsuccessful. VM6 doesn’t appear to harbor any misconceptions that their solution competes directly with VMware vSphere; they are focusing almost exclusively on cost and ease of use in their solution.

For more information on the VMex 2.1 release, see the VM6 Software press release.

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

VM6 VMex 2.1 Release

• Altor Announces VMsafe-Integrated Altor VF 3.0
• Live Migration and VM Failover for Oracle VM?
• Multiport Uplink Driver
• NetApp Adds Deduplication to Their VTL
• Virtualization Short Take #21

• Have I mentioned how useful the weekly VMware KB digests are?
• Frank Denneman has published a couple of really great articles recently. The first discussed how to remove an orphaned Nexus 1000V distributed virtual switch; the second discusses a complex interaction between HP Continuous Access and LUN balancing scripts. Both articles are worth a read.
• Similarly, Jeremy Waldrop has had a couple of good posts since he managed to get his hands on a Cisco UCS. The first post describes a “Doh!” moment when Jeremy realizes that adding more vNICs to a VMware ESXi instance with the Cisco VIC (aka “Palo”; sorry, Cisco, you’re not going to be escaping that code name any time soon) is really just a matter of specifying them in the service profile. I can certainly see where that’s not immediately intuitive. The other article describes Jeremy’s experience with using vNIC failover. There’s great information in the comments to that article; in particular, be sure not to enable vNIC failover with VMware vSphere. Bad things happen as a result. (OK, maybe not “bad things,” but network connectivity can be adversely affected. You should let VMware vSphere handle the NIC teaming and failover.)
• Toni Westbrook has a good article on how to move the COS VMDK in VMware ESX 4.0. Key note: this solution is currently unsupported by VMware, so use at your own risk.
• I’ve mentioned before how various bloggers often have a “masterpiece” post. This isn’t necessarily their most well-written post, but it’s the post that, for whatever reason, is a defining post for them. For me, it’s the ESX/VLANs/NIC teaming article I wrote in 2006. I think Jason Boche might have just come up with his: an in-depth discussion of the vpxd.cfg configuration options. Great information, Jason!
• In VDI environments, storage capacity is only one aspect of the overall storage equation. Vijay Swami at vEverything takes a pretty balanced view of how two leading storage vendors—EMC and NetApp—address not only storage capacity, but also IOPS. It’s worth a read and again underscores that there is no “one right way” to do things. Different doesn’t necessarily mean better or worse, just different. It’s all about the technology choices. (Disclosure: I work for EMC Corporation.)
• VDI on local disks, anyone? It’s an interesting discussion point that has its pros and cons. I guess the value of this sort of design really depends upon the business objectives the VDI implementation is trying to fulfill.
• Is anyone else amused by the abrupt “about face” that Microsoft performed with Hyper-V’s dynamic memory feature? Wow…even I was caught off-guard by how quickly they went from one end of the spectrum to the other. I would rather hear someone say, “You know, we were wrong, and this is a valuable feature after all” than to just flip 180 degrees and start moving in a whole new direction.
• Speaking of Microsoft and whole new directions…there was a great deal of coverage about Microsoft’s desktop virtualization announcement. I won’t try to delve into the details here; that’s a particular niche that is better served by those who have the time to dedicate to it. If you haven’t seen the news, my good friend Alessandro has a great write-up and there’s the official press release from Microsoft.
• If you’re interested in getting more information on RemoteFX—which appears, more than anything else, to simply be a set of LAN-only acceleration features for RDP and not an entirely new protocol—this article has good information. You might also have a look at this post about Service Pack 1 for Windows Server 2008 R2, which will enable both RemoteFX as well as the afore-mentioned Dynamic Memory.
• Continuing along with my little BSD love-fest, I came across this article that describes some strange behavior with CARP that can only be fixed by using link aggregation. The geek in me wants to go test this in a bunch of different scenarios to see if the Nexus 1000V fixes it or something like that, but I doubt that I’ll have the time.
• This is old news now, but in case you hadn’t heard VMware is licensing technology from Likewise Software for use with the next version of VMware vSphere. This will tighten vSphere’s integration with Active Directory. This is generally good, except that it will render my articles on ESX integration with Active Directory useless.
• With VMware vSphere 4.0 Update 1, you can now install EMC PowerPath/VE using vCenter Update Manager. This VMware KB article provides the details how it’s done.
• If you’re using ESXi and want to direct logging data elsewhere via syslog, this VMware KB article describes to configure syslog in ESXi.
• The ages-old discussion of scale up vs. scale out is revisited again in this blog post. I guess the key takeaway for me is the reminder that while VMware HA does restart workloads automatically, there’s still an outage. If you’re running 50 VMs on a host, you’re still going to have an outage across as many as 50 different applications within your organization. That’s not a trivial event. I think a lot of people gloss over that detail. VMware HA helps, but it’s not the ultimate solution to downtime that people sometimes portray it as.
• PHD Virtual has released esXpress version 4.0 today. I’ve taken a step back from most product announcements simply because they come too quickly to really keep up with them (unless you’re a madman like David Marshall over at VMBlog.com—my hat’s off to you, David!), but the timing worked out for this one. Go have a look at PHD Virtual’s web site for all the details.
• Last, but most certainly not least, my esteemed colleague Mike Laverick has completed his updated VMware SRM book, now updated for VMware SRM 4.0. Great work, Mike! I would wish you all financial success with the book, but as you’re giving it away for free (an admirable step, by the way) I guess I’ll just have to wish you all other forms of success!

That does it for me this time around, folks. Thanks for reading (I appreciate it!), and if you have some good information to add please feel free to speak up in the comments.

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Virtualization Short Take #37

• Virtualization Short Take #33
• Technology Short Take #2
• Virtualization Short Take #32
• Virtualization Short Take #38
• Technology Short Take #4

• Tom Howarth has been spending some time with Microsoft’s App-V application virtualization solution; he’s written a three-part series (Part 1, Part 2, and Part 3). Part 1 discusses domain and certificate setup, Part 2 centers around policies and GPO settings, and Part 3 covers the client-side setup for App-V. While Tom’s overview is extremely helpful, I don’t recall seeing any thoughts on App-V as a product. Tom, did you like it? Not like it? What was good or bad about it? It would be great to have a post that brings this sort of information together.
• Interested in getting a better feel for the communications that occur between an ESX/ESXi host and vCenter Server? This post discusses decoding SSL traffic with Wireshark so that you can see what’s happening.
• Jeremy Waldrop of Varrow has a good “getting started” post on using vCenter Server’s storage alarms. If you’re looking for an introductory piece, this is a good place to start.
• If you’re using Hyper-V and have VMs that are generating lots of network traffic, this post from the Windows Server Performance Team discussing increasing the VMBus buffer size is probably worth a look for you.
• And while I’m mentioning Hyper-V, Ben Armstrong aka Virtual PC Guy discusses an RDP ActiveX control that provides RDP connectivity to a VM (not RDP connectivity to the guest OS, which is distinct and separate). I’ve never been a huge fan of ActiveX controls, but this could be useful in certain environments.
• Is defragmentation of VMs a good thing? Scott Drummonds asks the same question in this blog post. My only comment: avoid defragmentation with thin provisioned disks (array-level or hypervisor-level thin provisioning).
• Of course, Scott Drummonds also had a flurry of very useful posts over the last few weeks: missing Perfmon counters, inaccuracy of guest performance counters, and Las Vegas taxi rates. (The Las Vegas taxi post actually helped me save some money when headed to the airport after PEX. Your mileage may vary—pun intended.)
• Eric Sloof’s home-grown tests of running linked clones on an SSD aren’t definitive, but they definitely back up the value that has been seen with the deployment of EFDs (Enterprise Flash Drives) in virtualized environments.
• This PowerShell script will show you the logged-in user for a given VMware View desktop. Handy!
• Readers seeking more information on guest OS alignment should read this article by Jeff Muir. While the focus of the article is on VHD and NTFS alignment, the underlying principles are also applicable to VMDK files in VMware environments.
• Frank Denneman, VCDX 29, has had a few good posts recently. He had a post that discusses the use of local storage for VM swap; this post was then parlayed into a greater discussion on understanding the impact of design decisions. It’s a pretty fitting discussion given the timing around all the VCDX defense panels at Partner Exchange and Frank’s own elevation to the VCDX priesthood. Frank’s article on VM sizing and NUMA was also a great read. Keep up the good work, Frank! (And I’m still waiting to see all the info about memory reservations you promised me…)
• Jason Boche recently highlighted his adventures in using Round Robin multipathing with his EMC Celerra. One key takeaway is that he had to reboot the ESX/ESXi host after changing the SATP, so keep that in mind. There is also a very specific CLARiiON configuration that needs to be set: the Failover Mode needs to be set to 4.
• Jonathan Medd provides some great information on users who might be new to vCenter Update Manager in this article.
• If you are planning on virtualizing any SQL Server systems, be sure to check out this list of best practices for SQL Server, written by Scott Drummonds. The document is a bit old (December 2008), but the recommendations are still valid.
• It appears that VMware has updated this KB article recommending the use of the LSI Logic vSCSI controller for low I/O environments. I’m glad to see VMware has added more information and clarification; the previous version of the article was a bit spartan, to say the least.
• I think that Figure 1 on this page on Cisco solutions for VMware View environments would give even Hany Michael a run for the money! While Figure 1 is pretty complex, the information in the article is useful and helps underscore some of the many different ways Cisco products can be put to use in a VMware View environment.
• Here’s a useful document on integrating Cisco UCS with VMware DPM.
• This weekly summary of new KB articles is quite useful. OK, I know this isn’t new and many people probably already knew about it but it’s still useful. So get off my case, OK?

There’s more that I could include, but I should probably wrap this up. Here are a few other links worth mentioning:

The Backup Blog: Avamar and VMware Backup Revisited
VMware KB: ESX 4.0 and ESXi 4.0 shutdown and reboot commands
VMware KB: Masking a LUN from ESX and ESXi 4.0 using the MASK_PATH plug-in
Rethinking vNetwork Security
Announcing NVSPBind

That’s it for this time around. Thanks for reading and feel free to submit any interesting links you’ve found in the comments!

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Virtualization Short Take #35

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• Virtualization Short Take #33

The session starts out with an overview of VMware snapshots followed by a quick overview of Microsoft Volume Shadow Copy Services.

Vasquez is careful to distinguish VMware snapshots from array-based snapshots, which is good since that seems to confuse a number of people. VMware snapshots can include the state of memory (optional), settings, and disk. Snapshots are taken at the VM level, and up to 32 snapshots can be taken. Over 20 snapshots can cause performance concerns and, in Vasquez’s words, “can cause undesirable results”.

In general, a snapshot will include all disks although there are ways to exclude disks from a snapshot.

Operations involving VMware snapshots include taking a snapshot (self-explanatory), reverting to a snapshot (reverts the VM to the snapshot state, the delta file remains until the snapshot is deleted), and deleting a snapshot (delta file is removed, VM continues running in the current state).

Some use cases for snapshots include: rollback capability for testing patches or updates; rollback for failed software installation; protection against unwanted results of OS reconfigurations or testing; backups (for creating consistent copies of a VM); and replication.

The delta file grows as-needed; over time, the delta file will grow larger and larger. Vasquez cautions attendees to be sure to plan datastore sizes to account for snapshots for VMs and the delta file growth caused by the changes to those VMs.

A good question was raised about read I/Os and the impact of snapshots (does

The presentation now moves on to a discussion of VSS. One component of VSS is the requestor; the requestor makes a request from a provider, and the writer provides information on how to provide information to a requestor. Providers are included with Windows and are responsible for intercepting I/O requests to create and represent volume shadow copies on the file system. There are also 3rd party providers. In this context of this discussion (VSS integration with VMware snapshots), VMware Tools is the requestor.

There is a wide range of applications that provide VSS support, including Exchange, SQL, SharePoint, Active Directory, BITS, DHCP, and WINS. The vssadmin list providers command will show all the providers. (Note that you won’t see the VMware Tools when you run this command; it is dynamically loaded only at snapshot time and then unloaded.)

The vssadmin list writers command will show a list of writers.

The general flow of operation with VSS runs like this:

1. Requestor makes a shadow copy.
2. The writer is told to freeze all I/O.
3. The provider creates a shadow copy.
4. The writer is told to “thaw,” or resume, I/O to the application.
5. The requestor now has access to the shadow copy.

The writer can support multiple enumerations, or different ways of coordinating the creation of the shadow copy. Exchange, for example, supports Full (backs up databases, logs, and checkpoints; truncates logs), Copy (backs up databases, logs, and checkpoints; does not truncate logs), Incremental (backs up and truncates logs), Differential (backs up logs but does not truncate). Of these, VMware uses the Copy enumeration when requesting shadow copies. Supposedly, the reason this is the case is to prevent interfering with backup applications that aren’t aware that logs were truncated. In addition, when VMware calls VSS, all writers are engaged, so it’s not possible to selectively choose which VSS writers should be engaged (can’t engage VSS for Exchange but not SQL within the same VM, for example).

In the future, VMware Tools will offer granular control over which VSS enumeration is used. Granular control over which VSS writers can be engaged is also planned.

Vasquez now moves into a discussion of how VMware snapshots and VSS integrate together. When a VMware snapshot is taken, this is when VSS integration comes into play. Obviously, for VSS integration the VM must be powered on (the guest OS must be running in order for VSS to be operational).

Some form of quiescing is always used when a snapshot is taken (unless the VM is powered off). The VMware Sync driver provides a crash-consistent copy of the VM but doesn’t interact with applications. This option is available in vSphere 4.0 and can be used when no VSS support from the application is available. Obviously, there is VSS support (hence this session), and there are pre- and post-quiesce scripts that can be used to create homebrew solutions as well. Both VSS and the Sync driver can be enabled using VMware Tools.

VSS support is enabled in VMware ESX 3.5 Update 2 or higher.

Going back to the VSS flow earlier, an additional step is present before the writer resumes I/O to take the VMware snapshot. After the VMware snapshot is taken, the shadow copy created by the provider is discarded because it is no longer needed. Once again, Vasquez reminds attendees that the VMware Tools Requestor only supports the copy enumeration.

An attendee asked if any plans were in place to do quiescing at the VMFS layer (supposedly to assist with hardware-based snapshots); Vasquez responds that some form of VMFS quiescing would be helpful, but there are challenges with that arrangement that make it currently very difficult to actually achieve.

(Vasquez also commented on the end-of-life policy for the ESX Service Console, but I’ll hold on mentioning what was said until I verify the confidentiality of the statement.)

Some additional things to remember:

• VMware Tools build must be 110268 or higher.
• VMware Tools must be running and VSS must be functioning properly.
• VSS Service must be set to Manual or Automatic.
• ESX 3.5 Update 2 is required for VSS support.
• Be sure VSS support is installed with VMware Tools.
• Try not to keep VMware snapshots around for a long time. Manage snapshots carefully.
• Sync driver can be used as a failback in the event VSS support fails.
• VSS snapshot has a 10 second timeout. Rare cases could cause a failure of getting the VSS shadow copy.

Most of the information contained in this presentation are found in the current vSphere documents and in Microsoft’s VSS documentation. (I’ll update this post with URLs when possible.)

And that’s it for the session.

This article was originally posted on blog.scottlowe.org. Visit the site for more information on virtualization, servers, storage, and other enterprise technologies.

Partner Exchange 2010 Session TECHBC0320

• VMworld 2007 Top Support Issues Session
• Snapshot Issue with VMware Data Recovery
• Recovering Data Inside VMs Using NetApp Snapshots
• Sanbolic Brings Snapshots to Melio FS
• Full VM Recovery with NetApp Snapshots