Re: RAID1 fail did not work properly with SSDs

[NeilBrown <neilb@suse.de>]

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On Thu, 5 Jan 2012 01:44:10 +0000 "Cal Leeming [Simplicity Media Ltd]"
<cal.leeming@simplicitymedialtd.co.uk> wrote:

> Hi all,
> 
> My apologies if this is the wrong mailing list for this issue, but I
> figured my email would be lost in volume if I sent to 'linux-kernel'.

too true!!

> 
> In short, I had 2 SSDs in RAID 1, allocated as a single physical
> volume, which had a LVM logical volume mounted as the root partition.
> 
> Six months later, one of the SSDs dies, and causes all of hell to break lose:
> 
> [27087.234675] sd 0:0:0:0: [sda] Unhandled error code
> [27087.234686] sd 0:0:0:0: [sda] Result: hostbyte=DID_BAD_TARGET
> driverbyte=DRIVER_OK
> [27087.234688] sd 0:0:0:0: [sda] CDB: Read(10): 28 00 00 68 53 88 00 00 08 00
> [27087.234693] end_request: I/O error, dev sda, sector 6837128
                                         ^^^^^^^^

"sda".

> ^^ repeated over 9000 times
> 
> Instead of the disk being marked as failed and removed, the root
> partition was instead remounted as read-only, mdadm showed no
> problems, and required a reboot.
> 
> Upon rebooting, RAID still hadn't marked the dying disk as failed or
> removed, and began to re-sync!
> 
>  root@vicky [/var/log] > cat /proc/mdstat
> Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4]
> md0 : active (auto-read-only) raid1 sdb1[0] sdc1[1]
                                      ^^^^^^^^^^^^^^^

"sdb" and "sdc".

Something is missing in this picture.

NeilBrown


>       78122967 blocks super 1.2 [2/2] [UU]
> 
> On top of this, even though it was read-only, it kept giving this
> error for everything:
> 
>  root@vicky [/var/log] > shutdown
> bash: /sbin/shutdown: Input/output error
> 
> I'm not sure if what I'm seeing here is normal, but thought I should
> at least try and ask - I can provide lots more info if needed (got a
> huge text file and several screenshots).
> 
> Any feedback would be very much appreciated.
> 
> Cal Leeming
> Simplicity Media Ltd
> 
> ----------------------------
> 
> Here is the short smartctl dump of the disk:
> 
>  root@vicky [/home/foxx] > smartctl -a /dev/sda
> smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build)
> Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net
> 
> === START OF INFORMATION SECTION ===
> Device Model:     M4-CT128M4SSD2
> Serial Number:    00000000111603061D7B
> Firmware Version: 0001
> User Capacity:    128,035,676,160 bytes
> Device is:        Not in smartctl database [for details use: -P showall]
> ATA Version is:   8
> ATA Standard is:  ATA-8-ACS revision 6
> Local Time is:    Tue Jan  3 13:54:46 2012 GMT
> SMART support is: Available - device has SMART capability.
> SMART support is: Enabled
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