New Article – Storage Design Principles

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I’ve added another new article to the articles section of the blog. This one is basically a high level storage design principles document aimed at giving those not so familiar with midrange storage design a bit of background on some of the things to consider when designing for VNX. It’s really just a collection of notes from information available elsewhere on the internet, so make of it what you will. As always, your feedback is welcome.

4 Comments

  1. Great article as always. I enjoy reading these when I get the time.

    One thing to mention about EMC’s metaLUNs for people that are not familiar with them. In the case of striped metaLUNs, one could think of them as RAID 50. In addition, anyone familiar with the EMC Symmetrix hyper concept would be familiar with striped/concatenated metaLUNs.

    If someone is familiar with the Symmetrix but not the Clariion/VNX, the formation of a striped meta from several hypers as the same as striped metaLUNs. metaLUNs can be a powerful tool if you need spindles behind a specific workload.

    Although pools can offer ease of management and certain features that metaLUNs cannot, however, from a performance aspect, metaLUNs still have a purpose by specifically targeting a disk bound performance problem.

  2. Dave, as always thanks for reading and thanks for the insight. The comparison with hypers is a good one – thanks for adding that. And as we’ve discussed previously – agree with you 100% on pools vs Metas. It was unfortunate I had to find out the hard way :)

  3. Great paper!

    just one thing may be worth to be additionally discussed: if you add a small bunch of disks to a pool new LUNs will be placed on these few disks until their capacitiy filling level is equal to the other disks. Only after that striping goes through all disks (private RAID groups) of the pool. That might create hotspots and reduce performance significantly in a scenario where you increase the number of disks in a pool step by step.

    simple solution: start with the final size of a pool. if you need to expand the capacity of a pool take enough disks or wait until a FLARE will offer new restriping capabilities ;-)

  4. Thanks Daniel. I’ve discussed the striping issue with Storage pools on the blog before, but you’re right, it is worth re-iterating.

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