Raid Drive Upgrades

Question

I have a RAID 5 setup with 5 2TB drives. If I start to replace the 2TB with 4TB, once I have enough, can the Array be moved to 4TB's? I know that if I put a 4TB in a 2TB Raid, the 4TB will recognize 2TB for the RAID.

What kind of (software/hardware) RAID controller are you using? — n.st, May 31 '16 at 22:29
Also note that upgrading a RAID **5** from 8 to 16 TB creates an entirely new set of problems: 1. Rebuilding a 16 TB array will take a significant amount of time, during which the remaining drives will be stressed and more prone to fail. With RAID 5, a second failure will kill your entire array. 2. Desktop-grade drives are only guaranteed to have less than 1 uncorrectable bit error every 12.5 TB, so there's a good chance you'll encounter an uncorrectable error that (depending on your RAID solution) might kill your array as well. Consider carefully if you might want to switch to RAID 6 instead. — n.st, May 31 '16 at 22:40

score 0 · Answer 1 · answered May 31 '16 at 23:24

It depends on what your RAID controller is. With software RAID on Linux - pretty much anything is possible. Quoting from man mdadm:

   Grow   Grow (or shrink) an array, or otherwise reshape it in some way.
          Currently supported growth options including changing the active 
          size of component devices and changing the number  of  active
          devices  in Linear and RAID levels 0/1/4/5/6, changing the RAID
          level between 0, 1, 5, and 6, and between 0 and 10, changing the
          chunk size and layout for RAID 0,4,5,6,10 as well as adding or
          removing a write-intent bitmap.

Hardware RAID controllers often supported limited array modifications. You will have to consult the documentation for your model if you are using one.

score 0 · Answer 2 · answered Jun 01 '16 at 03:27

A generic way to expand any raid array;

Update all disk like you already do. (one big one)
Create a backup.
Be sure the backup is good.
Now do a clone of the array/volume. Like an offline clone with a bootable acronis for server or symantec system recovery.
Erase/delete the raid array.
Recreate the raid array bigger with the new disk.
Reapply the clone, like acronis it even offer to resize the partition for you.

Raid Drive Upgrades

2 Answers2