[mythtv-users] RAID: full disk or partition (was: Question re: available SATA ports and linux software RAID)

John Drescher drescherjm at gmail.com
Thu Apr 28 02:02:30 UTC 2011


On Wed, Apr 27, 2011 at 9:33 PM, Jean-Yves Avenard <jyavenard at gmail.com> wrote:
> On 28 April 2011 00:23, John Drescher <drescherjm at gmail.com> wrote:
>
>> The problem with this solution is if you boot from a livecd or other
>> media that does not have your mdadm.conf it can force the /dev/sdd1 to
>> be failed if /dev/sdd is detected first.
>
> Rha...
>
> great ; done one disk (not sure if that one is faulty, but it was
> doing the resync at 20MB/s only that disk, while for the others it
> does is at 100MB/s+ usually)
>
> jyavenard at htpc:~$ sudo mdadm --detail /dev/md0
> /dev/md0:
>        Version : 00.90
>  Creation Time : Sat Apr  4 02:32:09 2009
>     Raid Level : raid5
>     Array Size : 7814047744 (7452.06 GiB 8001.58 GB)
>  Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)
>   Raid Devices : 5
>  Total Devices : 5
> Preferred Minor : 0
>    Persistence : Superblock is persistent
>
>    Update Time : Thu Apr 28 10:46:35 2011
>          State : clean
>  Active Devices : 5
> Working Devices : 5
>  Failed Devices : 0
>  Spare Devices : 0
>
>         Layout : left-symmetric
>     Chunk Size : 128K
>
>           UUID : c4da37ea:99c0fc03:a5e8058a:6a55fa23 (local to host
> htpc.avenard.org)
>         Events : 0.9743332
>
>    Number   Major   Minor   RaidDevice State
>       0       8       49        0      active sync   /dev/sdd1
>       1       8       65        1      active sync   /dev/sde1
>       2       8       33        2      active sync   /dev/sdc1
>       3       8       81        3      active sync   /dev/sdf1
>       4       8        1        4      active sync
>
> See on how the 5th drive doesn't have any device attached to it?

I have not seen that before. I am not sure what it means.

> jyavenard at htpc:~$ cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
> [raid4] [raid10]
> md0 : active raid5 sdf1[3] sdd1[0] sda1[4] sdc1[2] sde1[1]
>      7814047744 blocks level 5, 128k chunk, algorithm 2 [5/5] [UUUUU]
>

Now that looks good.

> jyavenard at htpc:~$ sudo mdadm --examine /dev/sda
> mdadm: No md superblock detected on /dev/sda.
> jyavenard at htpc:~$ sudo mdadm --examine /dev/sda1
> mdadm: No md superblock detected on /dev/sda1.
>

It looks like somehow the superblock got zapped on /dev/sda1
>
> Great, now where is my sda1 drive gone ? and how can I remove it and re-add it ?


Is there any message iin your dmesg about /dev/sda?

dmesg  | grep sda



-- 
John M. Drescher


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