RE: VMWare and Oracle IO
From: Michael McMullen <ganstadba_at_hotmail.com>
Date: Tue, 7 Oct 2014 12:46:09 -0400
Message-ID: <BLU177-W32962A87987F9324BD9866A6A20_at_phx.gbl>
Just went through this last week. I'll assume they are using paravirtual scsi drivers, which we were. We had massive latency which would show up intermittently, it would show up in oem as cpu wait for i/o. Also svctm on iostat were very high. I had already baselined the system to show that throughput had changed from 1Gb/sec to 20Mb/sec. Solution was to move all disk via ASM to new dedicated disks on the storage that bypassed the vm layer. No sharing with other vm's. Hopefully my terminology is right. That's what I was told that they provided me. I also have no idea if this problem went away due to low usage on the new dedicated san. We're doing vmotion testing on a sandbox to see if we still have vmotion capability.
Date: Tue, 7 Oct 2014 12:46:09 -0400
Message-ID: <BLU177-W32962A87987F9324BD9866A6A20_at_phx.gbl>
Just went through this last week. I'll assume they are using paravirtual scsi drivers, which we were. We had massive latency which would show up intermittently, it would show up in oem as cpu wait for i/o. Also svctm on iostat were very high. I had already baselined the system to show that throughput had changed from 1Gb/sec to 20Mb/sec. Solution was to move all disk via ASM to new dedicated disks on the storage that bypassed the vm layer. No sharing with other vm's. Hopefully my terminology is right. That's what I was told that they provided me. I also have no idea if this problem went away due to low usage on the new dedicated san. We're doing vmotion testing on a sandbox to see if we still have vmotion capability.
From: jkstill_at_gmail.com
Date: Tue, 7 Oct 2014 08:29:15 -0700
Subject: VMWare and Oracle IO
To: oracle-l_at_freelists.org
Fellow Oracleites:
I have been investigating a client database or two that have been experiencing IO problems since being virtualized via VMWare.
SA's claim no IO issues, but we have seen an Oracle IO take up to 3.5 seconds. Seems slow to me.
One thing I have learned is the the priority settings on VMWare disk shares can cause this issue for lower priority systems when the favored system(s) are requesting a lot of IO.
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Oct 07 2014 - 18:46:09 CEST