SQL server: RAID1 with SSDs or RAID10 with regular HDs?
I'm currently investigating a storage upgrade to help add a bit of fizz to our SQL server.
The server only has a SATA interface, so SCSI or SAS is out as an option. I have 4 drive bays. The server is also a Hyper-V host (not clustered) for other servers that are not disk IO intensive, but I need to maintain a reasonable amount of disk space for those (more than I can afford using just SSDs).
These are the two scenarios I'm considering:
- 2x SSDs in RAID1 for the SQL guest (probably the Intel 320s) + 2x 10,000RPM hard disks in RAID1 (for the other guests)
- 4x 10,000RPM hard disks in RAID10 for all guests.
My thinking is that in RAID10 the 4x HDs should reach a sustained transfer rate approaching or even exceeding the RAID1 SSDs, due to being able to read off of 4 spindles at once. Writing will be slower, but that's the same for SSDs too. However, I suspect that the reduction in seek times will give the SSDs the advantage.