I have a RAID 5 setup and I want to replace the drives with bigger drives.

I do not have an external drive big to make a backup, which rules out the traditional 1) Backup. 2) All new drives. 3) Restore option.

I do not have enough slots to make both arrays at the same time.

What are my remaining options?

Do I have to replace, rebuild, and repeat for each drive, or can I temporarily convert it to a RAID 0+1 to minimize rebuild times? What would be the most time-efficient way to replace each drive?

  • Is there an OS on the raid array? – Moab Oct 10 '15 at 14:43
  • @Moab Yes, there is. I can manipulate the RAID array while the server is online, but I would rather not due to performance. – oldmud0 Oct 11 '15 at 0:35

I ended up replacing and rebuilding each drive in online mode, making sure to disable hotswap before beginning the process.

After replacing all drives, I noted the RAID configuration, deleted it, and recreated it with the same exact settings except with the new size. I did not initialize the new configuration.

I restarted the server (all data was kept in the reconfiguration) and found the new space on the volume. I was able to just resize one of my partitions to fill the unused space.

  • 1
    Could you mention which RAID card you used? Some might support it and some will not, so someone looking though the site for answer would know if it applied to his/her card. – Hennes Dec 11 '15 at 4:59
  • @Hennes I used PERC 4/Di. Very old RAID adapter; I would expect most cards these days to do online expansion for you. – oldmud0 Dec 11 '15 at 5:04
  • Feel free to edit it in the post. These comments might eventually disappear. – Hennes Dec 11 '15 at 5:32

If you want to convert, you have to install all drives at the same time and copy the data. This is probably the fastest way.

If you want to keep the RAID5 and make the disks bigger you have to change one disk at a time and wait for resynch (and hope nothing goes wrong on the other disks at that time) or create a new RAID5 and copy data.

Depends on your system if the array could be grown after replacing disks with bigger ones.

If you have space for all the disks, it's always safer to copy data to the new ones.

  • What do you mean by copying data? I don't have an external drive so big and not enough slots to make both arrays at the same time. – oldmud0 Oct 10 '15 at 14:43
  • Then the only option is to replace drives one by one, synch, and then expand, if the controller allows it – Sami Kuhmonen Oct 10 '15 at 15:13

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