Convert Raid 5+Spare to Raid 5 without data loss?

I have my EX4100 configured as Raid 5+Spare. Don’t ask why; it seemed like a good idea at the time.

My question is, would it be possible to convert that to a normal Raid 5 without losing the existing data? My suspicion is, not. But it’s worth trying.

This was a technical question about what’s possible.

Essentially this thing is the backup/archive. Some stuff can be recreated, other would need to be preserved. Doable, but a pain.

Hi @dwillcox,

Have you opened a Support Case? If not opened, for more information, please contact the WD Technical Support team for the best assistance and troubleshooting:
https://support-en.wd.com/app/ask

I did submit a support ticket. So far no response.

Crickets on this support ticket: Support Login

Why am I not surprised? Your question is basically very simple. . .and should be able to be answered easily without drama… . and then EVERYONE could benefit from the response.

I am also curious to the correct answer. I suspect you cannot convert the array without wiping data. . .but I do not know.

I got a confirmation back from WD: Yes, changing the array size is destructive. “Back up your data” they say. A bit of an “ouch” when I’m basically using the thing as an archive.

Also no reply about whether it’s even possible to back up a TimeMachine backup, but I’m pretty sure that would be hard. I have other TM backups anyway, the NAS is just one version. Belts and suspenders, and duct tape.

ALWAYS have a data backup.

A NAS is not a foolproof backup. Vulnerable to Fire, viruses, rogue firmware updates, etc.
Cloud storage is not a foolproof backup. Vulnerable to missed payments; sudden changes in company policy; bankruptcy; viruses; etc.

Belts AND suspenders are a good strategy.

Bottom line:

  1. Changing from one Raid type to another is data destructive. (Raid 5+Spare to Raid 5, for example.) No way around this. You’ll need to back up anything you want to something, then copy it back when done.

  2. Changing to larger disks (2Tb drives to 4Tb, for example) can preserve data if you follow the procedure. But it’s probably quite time consuming. Backing up your data and then reloading maybe be a better option.