2011-05-09, 17:09
To add to Superob's post, a cache drive is recommend to be the larger than the amount of data you would aim to transfer for a 24 hour period but it doesn't have to be any particular size in comparison to your other drives. My Unraid build currently has a 2TB parity drive, 2x 2TB data drives, 2x 1TB data drives, 1x 500GB data drive and a 500GB cache drive, with the automated mover script occurring twice daily (as any data that is somehow lost whilst on the cache drive isn't protected).
EDIT: That said, it seems in your test you didn't have a parity drive either, which renders this whole discussion about parity calc being the bottleneck moot. If you had a parity drive and a data drive only for your tests, then that's the cause of your slower speed. If not, then I don't know.
EDIT: That said, it seems in your test you didn't have a parity drive either, which renders this whole discussion about parity calc being the bottleneck moot. If you had a parity drive and a data drive only for your tests, then that's the cause of your slower speed. If not, then I don't know.