I currently have 2 unraid servers setup, server 1 is comprised of a mixture of 2,3, and 4tb drives, the 2 and 3tb drives are 2 WD Blacks, 1 Seagate 2tb, 2 Hitachi 4tb, and 17 Hitachi older drives.

The 4tb drives are Hitachi 5 platter drives, all drives are 7200 rpm.

 

Server 2 is comprised of 17 3tb Seagate ST3000DM001's.

 

I am out of room on server 1 and getting close on server 2, I am looking to replace the older drives on server 1 and add more to server 2.

I am looking at the new Seagate NAS drives for both servers, my question is how much performance will I loose by going with these 5900 rpm drives vs 7200?

On Server #1 you'll probably not notice any performance impact => if anything, it'll probably be BETTER.    That's because the Seagate 4TB NAS units are all 1TB/platter drives -- with the improved areal density, the data transfer rate at 5900rpm is as good or better than 7200rpm drives with lower platter densities.    If you're doing transational processing, you'll see a bit of a hit, since the access times are a bit longer than with 7200rpm units; but for typical UnRAID use I'd expect either no impact or a slight improvement.

 

On Server #2 it's a different story -- you already have 1TB/platter drives there, so moving to 5900rpm drives will be a small reduction in performance.  I do NOT, however, think the difference will be noticeable for most applications => the most notable difference will probably be slightly longer parity check times.

 

Thank's for the info.