We are deciding whether to use SATA or SAS aggregates on our Filer for our VMWare datastore. We will be using NFS to connect the VMWare hosts to storage.
Doesn't seem to make sense to use SAS disks that have 6GB/s pipeline (15000 RPM) if it's going via NFS over gigabit network (1/8 GB/s). We are teaming the NIC cards but that's still 1/4 GB/s (in ideal conditions).
The SATA disks are 7200 RPM and, according to specs, 3GB/s.
Perhaps someone with more real-world experience could check my logic.
Additional information
- Both SAS and SATA aggregates have the same amount of disks.
Best Answer
The benefit of SAS is the number of IO/s they can do compared to SATA (or midline). SATA drives rotate more slowly (7200 RPM) and thus have a higher read latency. This is made worse by the fact that you'll have more VMs running per drive because of the high density of space. SAS drives that run at 10k or 15k RPM will have a much higher number of IO/s they can do per spindle.
You can put some loads on SATA, but I would use SAS for anything that can't afford slow response times.