I'm just about to build out a new SQL server that will host a number of databases that have high I/O requests. Normally i would build this out as follows:
OS: RAID 1 using onboard discs and controller.
SQL Server + SQL Logs: RAID 1 using a second pair of onboard discs and same controller as OS.
SQL Server DBs: RAID 5 across 13 discs of an external storage array with dedicated controller.
I have the option of creating a RAID 10 set using 12 of the 13 discs of the external array rather than RAID 5. RAID 10 generally gives better I/O performance over RAID 5 but will the two sets of 6 discs mirrored in RAID 10 give better I/O than 13 discs in RAID 5?
For my calculations i'm also using the (n-1)*0 equation where n=number of discs and 0=maximum I/O throughput per disc.
I'm still leaning towards the RAID 5 but thats because i don't have a great level of experience with RAID 10 arrays and their I/O throughput.
Thanks in advance.