7-Drive LUN?

PaulRS · partially protected Joined: 09 May 2008 Posts: 6

Does anyone know why Apple's configuration scripts for the VTrac only include 6-drive LUNs? It seems to me that a data-only E-J pair would be better with 4 7-drive LUNs with 4 hot spares. Is performance better with an even number of drives? If so why?

Thanks

nrausch · Xsan Master Joined: 14 Sep 2007 Posts: 202

FYI

I'm currently using 7 disk luns in multiple Xsans, doing HD video and finalcutserver. Have not had any performance issues.

mjsanders · Could work for Apple Joined: 02 Nov 2005 Posts: 59

I asked this specific question about even or un-even number of disk in an array, and the Promise Europe tech guy (Martin) told me there is no difference performance wise. More than 6 disks will not make the throughput a lot faster, only the size will be bigger.

The main reason for the 6 disk array is the fact that most installations need a meta-data lun and one (global) spare.

And if you expand a set with a second Vtrak, you want same-sized luns in your Xsan Volume, so again 6 disks.

If your metadata is stored somewhere else, you could use 7 disk raid5 luns with 2 spares if you want, but it will not be faster, only larger.