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I am considering an linux-based infiniband storage setup, but I am tripping over whether or not I can do active/passive or active/active failover with DRBD and SRP targets.

I am led to believe that SRP is the real problem here and that it may be supported on SCST, but perhaps not on LIO. There doesn't seem to be a lot of clear information online.

If I can't get this to work, I'll drop back down to iSCSI over IPoIB and take the attendant hits in performance and CPU utilization.

That said, can anyone set me straight as to whether SRP can handle multipathing/failover, and if not, why?

Thanks!

nrb
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  • Don't do it... I've seen lots of engineering hours wasted undoing homebrew DRBD (+Infiniband) storage solutions. No good can come of it. – ewwhite May 14 '13 at 20:55

2 Answers2

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You can achieve this by setting the WWN on both systems to be the same for a given DRBD device in LIO, and then using DRBD's dual primary option.

That way, the initiator sees what it believes to be the same disk on both servers and can use it's native failover/load-balancing.

This, however, is not supported by the DRBD people (yet). I gave it a miss and went with IPoIB iSCSI which is still very fast, especially for the price.

I'll move to iSER when it becomes available on my initiator.

nrb
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Setting up an active/passive storage setup with SRP, SCST and DRBD takes some work but it's doable. You will have to configure implicit ALUA though. There are detailed instructions in the SCST README for how to configure implicit ALUA. See also http://sourceforge.net/p/scst/svn/HEAD/tree/trunk/scst/README for more information about how to configure implicit ALUA.

user251384
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