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Re: Talking about RAID - disks with same id




On 8. Nov 2017, at 22:40, deloptes <deloptes@xxxxxxxxx> wrote:

> How is this possible and how to solve it - I would simply add 3rd 500MB disk
> to the raid and remove one of the others, but still what is the impact of
> this (stupid) coincidence …

I would not call it coincidence, what are the odds? There must be a reason for the identical UUIDs (1:1 copy of the disks?, restore of a partition table backup?), but it does not really matter.

I am quite new to this, but I guess you are not assembling your arrays by partition UUID, this should probably not work with identical UUIDs. As far as I understand most of the time the UUID of the array in the disks superblock is used for assembling and the partition UUID does not matter. Someone might be able to confirm this.

Of course there could be other parts of your system that use the partition UUID, but then again, if no issues occurred yet with two identical UUIDs, this is probably not the case, but this is hard to say.

You can change your partition UUID with fdisk (press x for extra functionality). An easy way to create a random UUID is:

$ cat /proc/sys/kernel/random/uuid

If you have the chance to test this, I would give it a try.

On 9. Nov 2017, at 08:17, deloptes <deloptes@xxxxxxxxx> wrote:

> has some effect and I should replace one of the disks. I think the Seagate
> is >10y old.

Then I guess you should replace the disk in anyway.

Cheers,
Tobi