Monday, December 09, 2013

Tips for storage performance on ESXi

There are a few tips for optmizing storage performance on ESXi 5.x. If you're using fibre-channel, one of the tips is to configure the LUN's as round-robin. You should also make sure that if multiple LUN's are presented from a storage array that they are all configured with the same path policy. Mixing round-robin and MRU or Fixed will create performance problems.

See the following article about setting path policy on ESXi hosts:

Path Policy in ESXi 4 and 5

The best way to do this on system which already has storage configured is to use a PowerCLI script to change the setting on all of the LUN's. Note, however that some storage devices should be set to fixed (i.e. non-ALUA Clariion devices and RDM's being used by MSCS).

Using PowerCLI to set path policy

Also, if you want any new LUN's to inherit the round-robin path policy by default you can modify the default setting for your specific storage vendor. The script at the end of the posting below is a good example. You will need to identify which type SATP your device is (e.g. VMW_SATP_ALUA).

Change Default Path Policy

I'm working on a couple scripts myself to do this and I will post them when they are polished up.