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Sybase on Linux on VMware Performance Questions

Question asked by Michael Adams on Sep 24, 2014
Latest reply on Nov 13, 2014 by Michael Adams

Hello all,

I am a recent LeftHand SAN convert and so far I am super happy with the move to Nimble.  I have a situation that I was hoping I could get some guidance on.  We are currently running Sybase 15.7 on RHEL 6.1 on top of VMware ESXi 4.1, in the past with LeftHand the best performance was when I presented the volumes to the Sybase server as RDMs and let VMware deal with the iSCSI connections.  However I have read the I will get better performance out of the Nimble SAN if I mount the volumes through iSCSI directly inside the Sybase server.  So my first question is to see if the Nimble world agrees that that is the best way to handle the mounting of the volumes?

Second, my Sybase server is setup to use 2KB block size and I notice that the performance policy will only let me go down to 4KB.  I have tried using the ESX performance policy(4KB) and found that it seems to work ok but the transfer rates seem to be real inconsistent and don't come close to maxing out the source SANs abilities.  I have also tried using the Oracle OLTP profile and found that to be painfully slow in the virtual machines, however in my DEV environment I have a couple of physical Sybase servers running the same OS and the same version of Sybase and when I use the Oracle profile my data transfers are rock solid and max out the source SANs abilities.  So now my second question is in the virtual environment what would the best solution be to get the max performance out of the volumes?