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Re: Talking about RAID - disks with same id

Le 10/11/2017 à 09:12, deloptes a écrit :

Joe Pfeiffer wrote:

Here's what I see when I look at my RAID disks:

/dev/sda2: UUID="67d3c233-96a0-737c-5f88-ed9b936ea3ae"
UUID_SUB="48b56869-6f19-21b9-283f-3eee3ac90cf8" LABEL="snowball:1"
TYPE="linux_raid_member" PARTUUID="3bb3729a-528b-4384-b6a5-b6d9e148ed2a"
/dev/sdb2: UUID="67d3c233-96a0-737c-5f88-ed9b936ea3ae"
UUID_SUB="1f48f805-4173-78cd-1f52-957920f66335" LABEL="snowball:1"
TYPE="linux_raid_member" PARTUUID="1bdd3893-9346-49d2-8292-a61075ad0c5e"

you see in your case PARTUUID is different for both members. In my case it
is identical and this is what is bothering me

and here's the relevant line in my /etc/mdadm/mdadm.conf
ARRAY /dev/md/1  metadata=1.2 UUID=67d3c233:96a0737c:5f88ed9b:936ea3ae

It looks like the new style raid

Indeed, superblock format 1.x. In addition to the "array UUID" which is common to all members of the array, it adds a specific "device UUID" for each member. blkid labels it "UUID_SUB".

However this raid was created ~12y ago without metadata.

I don't think so. If the array was created without metadata, blkid would not report the members as TYPE="linux_raid_member". It was rather probably created with the old metadata format 0.90. You can check with

mdadm --examine /dev/sd[fg]1