Storage Short Take #5

I’ve decided to resurrect my Storage Short Take series, after almost a year since the last one was published. I find myself spending more and more time in the storage realm—which is completely fine with me—and so more and more information coming to me in various forms is related to storage. While I’m far from the likes of storage rockstars such as Robin Harris, Stephen Foskett, Storagebod, and others, hopefully you’ll find something interesting and useful here. Enjoy!

  • This blog post by Frank Denneman on the HP LeftHand product is outstanding. I learned more from this post than a lot of posts recently. Great work Frank!
  • Need a bit more information on FCoE? Nigel Poulton has a great post here (it’s a tad bit older, but I’ve just stumbled across it) with good details for those who might not be familiar with FCoE. It’s worth a read if you haven’t already taken the time to come up to speed on FCoE and its “related” technologies.
  • What led me to Nigel’s FCoE post was this post by Storagezilla in which he rants about “vendor flapheads” who “are intentionally obscuring it’s [FCoE's] limitations”. You’ve got that right! Wanting to present a reasonably impartial and complete view of FCoE was partially the impetus behind my end-to-end FCoE post and the subsequent clarification. Thankfully, I think that the misinformation around FCoE is starting to die down.
  • This post has a bit of useful information on HP EVA path policies and vSphere multipathing. I would have liked a bit more detail than what was provided, but the content is good nevertheless.
  • Devang Panchigar’s recoup of HP TechDay day 1, which focused on HP StorageWorks technologies, has some good information, especially if you aren’t already familiar with some of HP’s various storage platforms.
  • Chad Sakac of EMC has some very useful information on Asymmetric Logical Unit Access (ALUA), VMware vSphere, and EMC CLARiiON arrays. If you using EMC storage with your VMware vSphere 4 environment, and you have a CX4, and you’re running FLARE 28.5 or later, it might be worthwhile to switch your path policy from NMP to Round Robin (RR).
  • Speaking of RR with vSphere, somewhere I remember seeing information on changing the default number of I/Os down a path, and tweaking that for best performance. Was that in Chad’s VMworld session? Anyone remember?
  • If you’re looking for a high-level overview of SAN and NAS virtualization, this InfoWorld article can help you get started. You’ll soon want to delve deeper than this article can provide, but it’s a reasonable starting point, at least.

That’s it for this time around. Feel free to share other interesting or useful links in the comments.

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  1. Duncan’s avatar

    esxcli --server nmp roundrobin setconfig --device --iops X --type iops

    minimum = 1
    default = 1000

  2. slowe’s avatar

    Duncan, I had to edit your comment a bit because WordPress likes to mangle hyphens and such. Let me know if that’s not correct…

  3. Ronny’s avatar

    Hi Scott,

    I think that’s the article from Chad Sakac about RR in vSphere you were looking for:



  4. slowe’s avatar

    Nope, that’s not it. Thanks, though!

  5. Rob D.’s avatar

    I second your request for clarification of the number of iops to use with vSphere and RR MPIO. The recent multi-vendor post on iSCSI mentions setting it to 3 if you use EqualLogic storage, however when I contacted EQ support and posted on the forum, I was told maybe 300 would be better, or my personal favorite “It depends so try a bunch of settings and monitor your performance for what works for you”. If anyone can shed light on this setting, please do so!

  6. Daniel Whittaker’s avatar


    Chad has updated information regarding changing the default number of IO before RR will switch paths in his most recent post, apparently it’s problematic atm:

    Not so good news :(

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