Hey everyone,
I have a customer upgrading to ESS Plus, so they can take advantage of the Vmware VSA.
They have 2, HP DL 360 G6's, 64 gb ram, 4x300 gb 15k sas drives each in a raid 5 stripe each host. Total 8 300 gbdrives at 15k.
Site is hosting about 17 vm, mostly reads, only the virtual Zimbra and terminal servervm's do any writes, but not much. 4ms read performance and 0 ms write on the host datastore.
While I was reconfiguring raid on one of the boxes, I came across a raid setting which determines write cache on the controller. Default is set to Off, Turning it on, the default is set at 25% read and 75% write, but can be set to 0/100, 25/100, 50/50, 75/25 or 100/0
This article recommends setting write cache to 0% read and 100% write, or 0/100 for HP Lefthand san VSA using Vcenter 5.1
"BTW – Highly recommend going 100% write cache on your controller if you are going to use RAID5 or 6."
Can anyone comment on this?
Second question, since cach host is using about 850 gb in local storage in a raid 5 stipe, times 2 hosts for about 1700 gb, how much storage will be left once the VSA appliance is configured.
I'm trying to weigh the cost/benefit of installing VSA, or, going with a hardware san.
Thank You!
Peter