Should I configure even number or odd number of disks for dynamic disk pools on MD3600F?
I have a Dell MD3600F with a MD1200 expansion. To my understanding, there is an advantage of using DDP instead of traditional RAID (say RAID 6), especially when it comes to data recovery.
The MD3600F has 12 x 4G SAS 7.2K disks and the MD1200 has 11 x 4G SAS 7.2K disks ( the original disk 12 on it has failed). When creating the DDP, should I use 20 x 4G disks or can I use 21 x 4G disks? Is there a performance difference between these two configurations ( I reserved one disk each from MD3600F and MD1200 aside as spare ones)?
You would need a minimum of eleven drives. Dynamic Disk Pooling (DDP) is based off of RAID 6, because of this 2 drives will be inherently reserved. A reservation size can also be set in MDSM, and varies based off of total drives in the pool.
The information we have here in our Dynamic Disk Pools Technical Report for MD3 series units can assist you in choosing the correct setup for your environment.
Thank you for helping on this. Yes, I understand the MD3 DDP requires a minimum of 11 drives. I have more than 20 drives for it (from my MD3600f and MD1200, 4T each instead of 4G in my original post). I wanted to know if there is any preference to use 20 disks or 21 disks. If there is no performance issue, I would like to use all 21 drives as it will give me additional 4T storage space.