EMC Storage – Design Considerations & Caveats
// September 26th, 2012 // Infrastructure, Storage
A recomended read on various design considerations and use cases for EMC storage pool provisioning. Vijay reviews in length 4 important caveat’s when implenting storage pools over RG’s.
“One very important aspect to understand is EMC’s recommendation to create R5 based pools in multiples of 5 disks. Again this is a VERY important thing to note because it could lead to unexpected results if you don’t fully understand this, and proceed to create pools from non-5disk multiples. The pool algorithm in FLARE tries to create the Private RAID5 groups for as 4+1 whenever possible. As an example, if you ignored the 5 disk multiple recommendation, and created a pool with 14 disks, you will NOT get the capacity you might expect. FLARE will create 2x 4+1 R5 Private RGs, and 1x 3+1 Private RG, NOT a single 13+1 Private RG that you may expect. So you would end up capacity which is lower than you are expecting.”
