EMC Clariion CX300 with VmWare - to Raid 6 or not to Raid 6?
Posted on 2009-04-25
We're using an EMC Clariion CX300 with 3 enclosures. Enclosure 0 is filled with 15x72GB disks, enclosures 1 and 2 are filled with 15x300GB disks each.
As of FLARE 02.26, EMC introduced RAID6 support for the CX300. The EMC is used only by three VMware ESX 3.5 servers.
My current plan looks as follows (all servers are virtual):
- The File-Server gets a 9x300GB disk RAID 6 (~1.75TB space)
- SQL Server gets a 4x72GB (120GB) Raid 10 for Logs and a 9x 72GB Disk RAID 6 (~450GB) for Data files
- Exchange Server gets a 5x300GB Raid 5 (~1TB)
- For all other servers (about 10 more VMs), I provide two 5x300GB Raid 5s
- One Hot-Spare Disk per Enclosure (1x72, 2x300GB)
- No plan so far for the remaining 1x 72GB disks and 4x 300GB disks
The provided space in this configuration should be more than sufficient until June 2013, when the support for our EMC expires and we need a new storage solution anyways.
File, SQL and Exchange server have by far the highest Average Disk Usage (File 5000KBps; SQL 2100KBps; Exchange 2400KBps). Peaks are hit during Backup (File, SQL) and Database Maintenance (Exchange), which happens at night with almost zero user load. All other VMs have very low average Disk usage, meaning <= 200KBps and no peaks except during backups.
My questions are:
- Do you recommend Raid 6 usage for the two 9-disk RAIDs? If not, please add your configuration proposal.
- How is the performance of RAID 6 comparing to RAID 5 with (our) EMC system?
- Generally, is it a good idea to make a RAID containing 9 disks?
- Any other objections about my current plan of RAID configurations?
Thank you in advance for your comments.