LUSE's distributed on different AG's - performance

[System Manager Wind]

I have a (maybe) simple question. Working on xp1024 and xp12000. Do I have real performance benefits by creating a LUSE made of some LDEV's taken each one from different AG's? Cannot find this info into any doc or white paper. I suppose yes, since I/O activities would be spread across different HDU's (and sometimes different ACP's). But XPPA is not able to get this info, since it targets only the first cu:ldev (the one that gives name to the LUSE itself) and (wrongly) assigns all traffic to its AG. Thanks for comments.
Luciano (luciano.garbolino@hp.com)

[ESC Team]

Hello Luciano,

Yes, distributing the LDEVs within a LUSE volume over multiple array groups will allow for better performance over the backend of the array.

Of course you can only use LDEVs (max 36) within the same control unit (CU) for a LUSE volume, so whether or not you get a good even spread of I/O is dependant on how the array has been installed and configured in the first place.

Whether or not the performance benefit is measurable, well, with the current tools available, that's a different story. The XPPT analysis tool (which creates a report from an exported Performance Advisor database) is currently the best option I think.

Anything that balances I/O across the FC-AL disk loops on the backend of the array is generally a good idea. YMMV.

Cheers, Maurice Clark.

[krusty]

One last item, if you create more than one LUSE - make sure the base volume is on a different AG. The base volume typically gets the most use, so if you have several LUSEs on the same AG, that AG gets hammered. So, "spread the wealth" to other AGs.

Curt

[System Manager Wind]

Hello Curt & Maurice, thank you very much for you comments! I'll sure take note and apply! Well, since XPPT is based on XPPA output I'm sure the same uncorrect response is shown into these charts (I mean, the apparent overload of AG's where a LUSE base cu:ldev resides), but obviously this is another story. Thaks again and ciao,
Luciano

[System Manager Wind]

I'm closing this thread but, if you have more comments, they are welcome at: luciano.garbolino@hp.com