I am tuning a disk sub system for our OLTP datebase server these
days. This is DAS disks. I now came into a question.
The server has 8 148GB SAS drives. To have fault tolerance, we want to
have RAID mirroring, so RAID 1 or 10. That leaves us half of the
whole capacity, which is 4 * 148GB. As this box is only used for
database, we want to have partitions for OS, data file, log file and
temp db. Now I there is a dilemma:
I know for best practise, temp db should on its own physical disk. If I set up four partition(logical drives), one for OS, one for data
files, one for logs and one for temp db, then I can only have RAID 1
on each of the disk array. But the advantage of this is temp db is
only its own disk.
Or the second choice I can have is to partition the disks into three
array (logical drives), namely OS, data files and logs. In this case I
can have RAID 1+0 (striping and mirroring) on data file partition and
RAID 1 on OS and log.
Could you give me some idea, which one is better? Any
disscussions are welcome. Thank you very much.