Can you mix SSD and HDD's in the 5D for tiering?

I understand that the 5D has a single mSATA port for speeding things up. presumably, it’s a read-only cache, as without any redundancy, it wouldn’t be safe as a write-cache.

i don’t know this - i only assume it to be so.

My question though is if i can install, lets say, two SSD’s and 3 HDD and have the 5D automagically do tiering between them, much like is currently done in the higher end drobo.

I need to host a busy email server plus some other workloads, so i need really good read-write performance for small files, and i need about 4-5tb total capacity.

two 500mb ssd’s, three 4 tb hard drives, and perhaps an mSATA for good luck, and i’d have a pretty sweet ride, presuming, of course, the ssd’s are used for tiering and not just blindly stripped together with the HDD’s.

The 5D doesn’t do the same kind of data-aware tiering that the B1200i does, as it doesn’t have enough drive bays to create two separate data tiers. The 5D will not have the IOPS needed to run VMs, serve files and be a storage backend for a mail server and an SQL server. These are the types of tasks for which we recommend a B1200i with a transactional tier, which tops out around 2300 IOPS. Our KB article regarding IOPS can be found at

To determine how many IOPS the server is using, follow the instructions at This will help you determine the type of equipment you would need to replace the Xserve.

Thanks Sky, very helpful information. I’ll follow your advice and run some tests.

about the tiering thing, i don’t see how the lack of drive bays would be the reason to not enable tiering in the 5D. there’s a total of 6 bays there. 1 x mSata, 1 x ssd, 4 x hdd. what’s the problem?

perhaps tiering needs significantly more ram to work properly with a larger flash tier, and the 5D must not have enough?

either way, it’s an unfortunate shortcoming.

here’s an idea - the 5D+, with two HOT SWAPPABLE mSata ports for mirrored read-write caching and data tiering.