boyedav
Contributor
Contributor

VMWare iSCSI software initiator: enterprise-ready?

We've been using iSCSI HBAs in our VMWare servers since they went into production last year, and they've worked great. We're ready to pull the trigger on 10 GbE iSCSI, but the one thing holding us back is the availability of 10 GbE iSCSI HBAs.

One option would be to put some supported 10 GbE NICs in our VMWare servers, and then use the software iSCSI initiator to do iSCSI over the 10 GbE port. However, since we've not used VMWare's software initiator before, I'd be interested in hearing from those of you who have. All of our virtual machines live on an iSCSI SAN, so it's important that the software initiator is every bit as stable and reliable as the hardware HBAs we've been using.

Our new VMWare servers have more than enough space CPU cycles, so I'm not worried about the overhead of TCP encapsulation at all. I just want to know that the iSCSI software initiator can survive in production.

Correct me if I'm wrong: you can't currently configure the software initiator for jumbo frames, but that's slated for an upcoming release?

Thanks!

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8 Replies
Gerrit_Lehr
Commander
Commander

You are right, jumbo frames are currently not supported for iSCSI and NFS.

I used Software iSCSI on ESX for a while, even though only in a test environment, and it worked very well and stable, even unter VMotion and on high workloads. Using certificated NICs and Storages should be the right way and I did not hear of cases where the SW iSCSI caused unusual trouble in productive environments.

Kind Regards,

Gerrit Lehr

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Kind regards, Gerrit Lehr If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".
williamarrata
Expert
Expert

You may want to review this document.

Hope that helped. Smiley Happy

Hope that helped. 🙂
Gerrit_Lehr
Commander
Commander

This document may provide some useful information aswell:

http://www.vmware.com/resources/techresources/1046

Kind Regards,

Gerrit Lehr

If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".

Kind regards, Gerrit Lehr If you found this or other information useful, please consider awarding points for "Correct" or "Helpful".
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kjb007
Immortal
Immortal

The only problems I've read about the sw initiator so far has been the initial configuration, and it's usually been the fault of the array, and not the initiator. Other than that, the only other issue is removing LUNs, which can get a bit annoying. No other issues I have heard about, and the initiator itself has been very stable. I've read just as many if not more issues with some other HBA's, so I'm of the oppinion that the sw initiator works just as well.

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB
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Rumple
Virtuoso
Virtuoso

I've found that after reboots the iscsi initiator doesn't see the LUN's anymore and its hell to get it bakc up and running (removing config, rebooting, and resetting up the iscsi to get it working). all other attempts at rescan's, disable/re-enable,etc were unsuccessful.

I moved to NFS and haven't had an issue since even after multiple reboots.

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matuscak
Enthusiast
Enthusiast

We've been using the software iSCSI exclusively and have never seen anything like what you're describing. I suspect that is more likely a function of your SAN, rather than the ESX initiator. What are you using?

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kjb007
Immortal
Immortal

I agree. I've never seen issues as you describe. I've had issues removing access to a LUN, but never issues with a LUN being "un-mapped or unconfigured" as you suggest.

-KjB

vExpert/VCP/VCAP vmwise.com / @vmwise -KjB
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Rumple
Virtuoso
Virtuoso

At the time it was the cx700 with the iSCSI enabled. If you search the forums for iSCSI there are lots of others hitting that too as thats how my iSCSI newbie ass was figuring out how to disable/renable and rescan using command lines,etc.

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