When setting MAX_IOPS_PER_VOLUME in a Resource Pool, what exactly does "volume" mean? Specifically, how many "volumes" would be the following cases:
- Locally attached disk that's split into two partitions E: and F:
- Software RAID 1 set E: composed of 2 locally attached disks (yes I know software RAID is bad– adding this case to help me understand SQL Server's definition of "volume", not to design a production setup!)
- Hardware RAID 1 set E: composed of 2 locally-attached disks
- SAN disk E: on who knows/who cares how many disks.
- 1 SQL Server filegroup spread across two locally attached disks E: and F:
I assume the answers to #3 and #4 are "1 volume" and #5 is "2 volumes" but it's #1 and #2 that I'm most curious about.
The specific reason I'm asking is wondering if it's possible to increase the Resource Governor's IOPS limit for locally-attached SSD tempdb while having a lower limit for our SAN data storage.
So I'm wondering if splitting a single physical disk into multiple partitions might be a way to do this, by putting separate tempdb files on each partition so the total tempdb If #1 above makes SQL Server treat one physical disks as multiple volumes for throttling purposes, this may be an option. I'm assuming that this won't work– that SQL Server is smart enough to know that 2 partitions is one "volume". But was worth asking.