From: Phil Turmel <philip@turmel.org>
To: Dave Gomboc <dave_gomboc@acm.org>
Cc: linux-raid@vger.kernel.org
Subject: Re: raid10 recovery assistance requested
Date: Mon, 23 Sep 2013 00:12:26 -0400 [thread overview]
Message-ID: <523FBFAA.3050705@turmel.org> (raw)
In-Reply-To: <CA+dwz-2qqYbL1uFmL+vnS=ht6ZHxMDkRRBUYPz0KFQZNZkeK-A@mail.gmail.com>
On 09/23/2013 12:04 AM, Dave Gomboc wrote:
>> Ok. I can't determine how the superblocks ended up the way they did,
>> but the first two chunks appear to follow the proper patterns.
>>
>> I think you're best bet is to disconnect two of the drives, leaving one
>> that identifies as "0" and one that identifies as "3".
>
> root@sysresccd /root % ls -l /dev/disk/by-id | grep Hitachi | grep -v part1
> lrwxrwxrwx 1 root root 9 Sep 22 20:17
> ata-Hitachi_HDS724040ALE640_PK1310PAG5ZY0J -> ../../sdb
> lrwxrwxrwx 1 root root 9 Sep 22 20:17
> ata-Hitachi_HDS724040ALE640_PK1310PAG62REJ -> ../../sdc
> lrwxrwxrwx 1 root root 9 Sep 22 20:17
> ata-Hitachi_HDS724040ALE640_PK1310PAG62T2J -> ../../sdd
> lrwxrwxrwx 1 root root 9 Sep 22 20:17
> ata-Hitachi_HDS724040ALE640_PK1311PAG4W5TS -> ../../sda
> root@sysresccd /root % cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
> [raid4] [raid10]
> md127 : inactive sdd1[3](S) sda1[0](S)
> 3907021954 blocks super 1.2
>
> unused devices: <none>
>
> Should I be disconnecting sdb and sdc, disconnecting sda and sdd, or
> does it matter?
Actually, from that report, just do "mdadm /dev/md127 --run".
> I should reboot using the rescue disk before attempting the forced
> assembly, not my boot drive, right?
Yes, but only necessary if the above fails. And if there's a partial
assembly, you might need to use "mdadm --stop".
> Sorry if the answers to these questions seem obvious to you: I want to
> make sure that I understand you exactly. I am moderately terrified at
> the moment.
You have duplicated the disks. You have all of the insurance possible.
>> Then use "mdadm -Af /dev/mdX /dev/sdY1 /dev/sdZ1"
>>
>> The "-f" will force the assembly without regard to the event counts.
>> Then you can take a backup. Finally you can add devices as "new" ones
>> to rebuild back to full redundancy. (Fix your timeouts before
>> attempting the latter.)
>
> When following up on your advice to search for those other terms, I
> saw several examples where people specified 7 seconds to the disk
> drive using that control program, and also read somewhere that while
> Linux's software raid will wait, that Linux's scsi subsystem has a 30
> second timeout. So, 7 seconds sounds good?
Most traditional enterprise drives power up with t=7 seconds. The SSDs
I've used use t=4 seconds.
Keep in mind that the setting is forgotten when the drive powers down.
You need the commands in rc.local or your distro's equivalent.
Phil
next prev parent reply other threads:[~2013-09-23 4:12 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-16 3:30 raid10 recovery assistance requested Dave Gomboc
2013-09-19 3:20 ` Dave Gomboc
2013-09-19 4:29 ` Stan Hoeppner
2013-09-20 5:29 ` Dave Gomboc
2013-09-22 17:15 ` Dave Gomboc
2013-09-22 21:52 ` Phil Turmel
2013-09-22 22:45 ` Dave Gomboc
2013-09-22 23:04 ` Dave Gomboc
2013-09-22 23:25 ` Phil Turmel
[not found] ` <CA+dwz-0eskPSQ44v0vgwfjwRpTbQaokQ3Q258Em1W2eRi1SO4w@mail.gmail.com>
2013-09-23 2:54 ` Phil Turmel
2013-09-23 3:19 ` Dave Gomboc
2013-09-23 3:27 ` Phil Turmel
2013-09-23 3:34 ` Dave Gomboc
2013-09-23 3:51 ` Phil Turmel
2013-09-23 4:04 ` Dave Gomboc
2013-09-23 4:12 ` Phil Turmel [this message]
2013-09-23 4:55 ` Dave Gomboc
2013-09-23 5:07 ` Dave Gomboc
2013-09-23 5:19 ` Adam Goryachev
2013-09-23 12:32 ` Phil Turmel
2013-09-23 12:57 ` Dave Gomboc
2013-09-24 0:29 ` Adam Goryachev
2013-09-24 5:55 ` Dave Gomboc
2013-09-28 15:47 ` Dave Gomboc
2013-09-28 16:01 ` Phil Turmel
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