ASM Disk Group RAID Levels
griddbaOct 7 2008 — edited Oct 13 2008This is the scenario that I am currently working on. Just need some input on whether it is feasible or not.
We have a 2 node RAC running Oracle 10.2.0.3 on AIX 5L. Database size is ~2TB. The database mostly performs OLTP but also stores some historical data.
There are two main applications using the database - one performs high reads with some small updates & inserts, while the other is very write intensive but does some reads as well.
Currently there are three disk groups one for the tablespaces (dg_data), another for system/sysaux/undo tablespaces (dg_system) and another for archived logs & redo log copies (dg_flash) - all using external redundancy. ASM best practises recommend no more than 2 disk groups. It also recommends disk groups with disks of similar characteristics including raid levels. However, the dg_data disk group has both RAID 5 and RAID 1+0 disks which house tablespaces for both applications. Seeing that the applications have different requirements (heavy reads vs heavy writes) does it make sense to create a separate disk group with 2 different RAID levels or would using RAID 5 in dg_data satisfy both requirements?