topic Re: EVA8100 LUN queue depths in Disk Enclosures

EVA8100 LUN queue depths

David Lewis_1 — Wed, 05 Nov 2008 13:09:29 GMT

Does anyone no if the LUN's created on the EVA8100 have there own i/o queue depth or is the queue depth handled by the HBA and O/S

Re: EVA8100 LUN queue depths

IBaltay — Wed, 05 Nov 2008 13:17:19 GMT

Hi,
maybe this discussion could help you (there are posts also on the queue depths (execution throttles) there:
http://forums11.itrc.hp.com/service/forums/questionanswer.do?admit=109447626+1225890722661+28353475&threadId=1239472

in general, the best values are OS/app/storage dependent... (to reach the optimum between the writes/reads, etc.)

Re: EVA8100 LUN queue depths

David Lewis_1 — Wed, 05 Nov 2008 13:28:35 GMT

Ibaltay - thanks for the reply - however what I am trying to determine is if the EVA virtual LUN's have there own queue depth setting, which it is either possible to modify or check for performance.

Re: EVA8100 LUN queue depths

IBaltay — Wed, 05 Nov 2008 13:55:12 GMT

Hi, yes it can be modified either via
a) the HBA BIOS
b) the qlogic SAN surfer or emulex HBA anywhere utilities

Re: EVA8100 LUN queue depths

Mark Poeschl_2 — Wed, 05 Nov 2008 17:45:35 GMT

I fairly sure this HAS NOT changed with the next generation controller that's in the EVAx100 series. EVA controllers have a single queue into which ALL LUNs' I/O gets placed. Any per-LUN queue depth settings are done on the OS/HBA side.

Re: EVA8100 LUN queue depths

David Lewis_1 — Wed, 05 Nov 2008 18:07:50 GMT

Super - thanks for that - however any idea what size the max queue depth is on the controller

Re: EVA8100 LUN queue depths

IBaltay — Wed, 05 Nov 2008 19:14:33 GMT

Hi also e.g. this doc could help you:
http://www.qlogic.com/SiteCollectionDocuments/Education%20and%20Resource/whitepapers/whitepaper2/FC0054602-00.pdf