On Sep 15, 2009, at 3:43 PM, Majed B. wrote:
Weird. I haven't seen that before on my disks/partitions. user@Adam:~$ ls -l /dev/disk/by-uuid/ total 0 lrwxrwxrwx 1 root root 10 2009-09-14 18:05 cf70cb2b-8e1e-44f3-b361-4a27e169eef2 -> ../../sdi1 lrwxrwxrwx 1 root root 10 2009-09-14 18:05 f54698f9-72a0-4226-9ada-34af2699a25c -> ../../sdi5 My array is offline at the moment, so I can't print the disks' info, but as you can see, each partition has its own UUID, and if each partition belonged to a different array then it would have a different UUID.
As did Matthias' setup. However, if you fail to read the partition table on a device, *and* the superblock on any given partition is in the exact same location as it would be if you put a superblock on the entire device, then mdadm can get confused and think the superblock belongs to the entire device and not just the partition that the superblock is at the end of. When that happens, it will think the data starts at block 0 of the drive, instead of block 0 of the partition and the data read will be inconsistent. That's what happened to Matthias.
Sorry for your loss :/On Tue, Sep 15, 2009 at 10:33 PM, Matthias Urlichs <matthias@xxxxxxxxxx > wrote:On Tue, 2009-09-15 at 22:24 +0300, Majed B. wrote:Specifying partition names may cause problems if the disk names changed. Specify the UUID instead.What I was trying to say is "use a pattern that matches all of your partitions and none of your actual disks". That should be safe from changing disk file names.Besides, specifying UUIDs does not work because it runs into the exactproblem we're trying to solve in the first place. Behold the "blkid" output from the server in question: /dev/sdb2: UUID="1583e643-7004-a86e-4eff-81c58ea53278" TYPE="mdraid" /dev/sdb: UUID="1583e643-7004-a86e-4eff-81c58ea53278" TYPE="mdraid"Interestingly, for some reason it doesn't do that with /dev/sda -- most probably because the disks in question use different head/sector valuesand thus have slightly different partition layout.-- Majed B. --To unsubscribe from this list: send the line "unsubscribe linux- raid" inthe body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
-- Doug Ledford <dledford@xxxxxxxxxx> GPG KeyID: CFBFF194 http://people.redhat.com/dledford InfiniBand Specific RPMS http://people.redhat.com/dledford/Infiniband
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