Posts Tagged ‘RAID’

EMC Clariion RAID Group Recommendations

October 4, 2009

Last week we had a client that needed a replacement disk drive for an older EMC Clariion array.  Now this is by no means anything complicated but the drive needed wasn’t available anymore.  The questions was posed, “ Can you mix 15k and 10k fibre channel drives in the same RAID group?”  Hmmmmm, I hadn’t run across this yet so I had to look it up.  The short answer is YES you can but it’s not best practice.  So what is the best solution in a case like this?  Simple, buy a larger capacity drive of the same speed (10k rpm, 15k rpm) and use it in place of the failed drive.  You’ll lose the additional capacity of the drive but the performance won’t be affected.

In the process of looking for the official answer to this question I came across several other little tidbits that are good information to know about Clariion arrays in regards to drives.  To give credit where it’s due most of this and additional info can be found at

–          All disks in a RAID group will match the smallest capacity drive.

–          The Vault Drives in a Clariion MUST all be the same size.

–          SATA and FC drives can NOT be mixed in the same disk tray or DAE

–          SATA drives can only use a SATA Hot Spare and FC drives can only use a FC Hot Spare

–          A 15k FC drive can use a 10k Hot Spare and vice versa.

–          A DAE allows one speed change within the shelf but it is recommended to have all the same speed drives in a DAE.

–          If drive speeds will be mixed in a DAE the faster drives should be installed in the leftmost drive slots first.