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Troubleshooting Random Read Issue

Occasional Visitor

Troubleshooting Random Read Issue

Hey Adam,

I'm performing SQLIO tests on a CS220, configured iops=0 an bytes=0, 4 x 1G interfaces on both Nimble and ESX, NO Jumbo Frames, and connecting to a CISCO 3750 stack. I am receiving expected results in IOPs numbers with exception of Random Read. Can you post your Cisco interface port configs for the Nimble and also for iSCSI? Ex..."flowcontrol received desired"..."spanning-tree portfast"...etc.  And did you enable Jumbo Frames? Here are my results:


Volume: VMFS 5 4K

Random Writes: ~35,000 IOPS / ~275 MB/sec

Random Reads: ~21,000 IOPS / ~160 MB/sec (low numbers...expecting higher numbers in the ~40,000+ much like Shawn Peters)

Seq Writes: ~20,000 IOPS / ~160 MB/sec

Seq Reads: ~6,600 IOPS / ~419 MB/sec

Why are the Random Reads so low? Should the numbers be up in the 40,000+? Any help is appreciated?

Trusted Contributor

Re: Troubleshooting Random Read Issue

There is a bug in Cisco IOS versions prior to 15.0(2) on the 3750 that can keep flowcontrol from being on even when the port settings are desired or forced on. This may or may not be your issue but I would suggest upgraded to this IOS release and if this does not resolve your issue then contact Nimble support and they can help you troubleshoot.