The following summarizes Dell EMC best practices for ASM diskgroup design when deployed on ScaleIO:
- Dedicated or shared diskgroups—Do not mix production and non-production workloads into the same diskgroups. Use dedicated ASM diskgroups where ScaleIO functions such as snaps will be used for a single database.
- How many diskgroups?—Basic configuration is DATA and FRA. RAC adds GRID. Additional disk groups may be evaluated based on application needs.
- ASM disk sizes and counts—Dell EMC recommends a minimum of four ASM disks per ASM diskgroup.
- Redundancy—Dell EMC recommends using EXTERNAL redundancy in all ASM diskgroups. See exception for ASM diskgroups where voting disks are stored.
- ASM AU size—Dell EMC recommends an AU size for OLTP workloads of between 1 MB and 4 MB, and an AU size for OLAP workloads of 16 MB or greater.
- Coarse or fine grained striping—Dell EMC recommends fine grained striping for control files, redo and flashback logs. Coarse grained striping should be used for all other files.
- Migrations—During migrations add all new disks and remove all old disks with a rebalance power setting of zero. Then rebalance the entire diskgroup in a single step.