Mix different speed hard drives on same raid

[fiza]

Is it possible to have a RAID 5 array with 3 x 10K disks and 1 x 15K disk?

 

I mistakenly got a 15k replacement disk a few months back which I would like to use but the other 3 disks which make up the RAID 5 are 10k disks. All disks are from Dell and designed for the Server. Will this cause me any problems or will the 15k just drop down to 10k speed? My main priority is creating more space.

[strawberry]

the array will run at the lower speed, so will run as before. Go for it!