Replacing a disk with a disk of different size in Transparent RAID

Use Case

The most common use case for this scenario is if you wish to replace a smaller disk with a larger disk regardless of whether the disk in the array has failed or not.
Note that a failed disk must always be recovered.

Fastest Approach (recommended for non-failed disk)

- Copy the file & folder content from the old disk to the new disk
- Stop the Storage Pool and array
- Delete the RAID configuration
- Create a new RAID configuration with the new disk
- Initialize by doing nothing
- Verify & Sync after the array is back online

The Alternate Approach (for non-failed disk)

- Remove the old disk (RAID Contraction)
- Copy the file & folder content from the old disk to the new disk
- Add the new disk (RAID Expansion)

How about recovering the old disk into the new disk? (not recommended even for failed disk)

One might be tempted to recover a failed disk into a new larger replacement disk.
This approach requires after the Restore operation that:

  • you first Verify & Sync the array range above the size of the old disk. For instance, if replacing a 2TB with a 4TB, you will need to run a Range Verify & Sync starting at 2TB and stopping at 4TB after the Restore operation completes.
  • use a third party software to extend the partition to make use of the new disk’s full size. When restoring a smaller disk into a larger disk, the volume(s) that existed will remain the same size. You will need a third party software such as Partition Magic to extend those volumes. That or you will need to create new partitions on the new disk.

What if we have a failed disk and the only replacement disk we have is a larger disk?

- Copy the file & folder content from the failed tRAID disk to the new disk
- Stop the Storage Pool and array
- Delete the RAID configuration
- Create a new RAID configuration with the new disk
- Initialize by doing nothing
- Verify & Sync after the array is back online

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Revisions

2 Responses to “Replacing a disk with a disk of different size in Transparent RAID”

  1. Chris McFaul November 19, 2014 at 4:32 AM #

    “- Copy the file & folder content from the failed tRAID disk to the new disk”

    surely if its failed then you CAN’T copy the content off it.. that is the point?

  2. Kim Andersen January 31, 2015 at 2:06 PM #

    Hi

    Think the last section(“What if we have a failed disk and the only replacement disk we have is a larger disk?”) should be placed at http://wiki.flexraid.com/2013/06/27/restoring-a-failed-disk-in-transparent-raid/, because typically one would buy a disk as large as the ppu and the failed disk maybe smaller than the ppu. At least a reference to this article would be nice.

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