From: Nagilum <nagilum@nagilum.org>
To: Mike Hartman <mike@hartmanipulation.com>
Cc: Jon@ehardcastle.com, linux-raid@vger.kernel.org
Subject: Re: Accidental grow before add
Date: Tue, 28 Sep 2010 17:14:51 +0200 [thread overview]
Message-ID: <20100928171451.27293d0o1kotcfi8@cakebox.homeunix.net> (raw)
In-Reply-To: <AANLkTimWyuvf1_9H8QhLXQ5gYRya1ux6WFGS4EPWP5_U@mail.gmail.com>
----- Message from mike@hartmanipulation.com ---------
>> I am more interested to know why it kicked off a reshape that would
>> leave the array in a degraded state without a warning and
>> needing a '--force' are you sure there wasn't capacity to 'grow' anyway?
>
> Positive. I had no spare of any kind and mdstat was showing all disks
> were in use.
Yep, a warning/safety net would be good. At the moment mdadm assumes
you know what you're doing.
> Now I've got the new drive in there as a spare, but it
> was added after the reshape started and mdadm doesn't seem to be
> trying to use it yet. I'm thinking it's going through the original
> reshape I kicked off (transforming it from an intact 7 disk RAID 6 to
> a degraded 8 disk RAID 6) and then when it gets to the end it will run
> another reshape to pick up the new spare.
Yes, that's what's going to happen.
>> Also, when i first ran my reshape it was incredibly slow from
>> Raid5~6 tho.. it literally took days.
> I did a RAID 5 -> RAID 6 conversion the other week and it was also
> slower than a normal resizing, but only 2-2.5 times as slow. Adding a
> new disk usually takes a bit less than 2 days on this array and that
> conversion took closer to 4. However, at the slowest rate I reported
> above it would have taken something 11 months - definitely a whole
> different ballpark.
Yeah that was due to the disk errors.
I find "iostat -d 2 -kx" helpful to understand what's going on.
> At any rate, apparently one of my other drives in the array was
> throwing some read errors. Eventually it did something unrecoverable
> and was dropped from the array. Once that happened the speed returned
> to a more normal level, but I stopped the arrays to run a complete
> read test on every drive before continuing. With an already degraded
> array, losing that drive killed any failure buffer I had left. I want
> to make quite sure all the other drives will finish the reshape
> properly before risking it. Then I guess it's just a matter of waiting
> 3 or 4 days for both reshapes to complete.
Yep, I once got bitten by a linux kernel bug that caused the RAID5 to
corrupt when a drive failed during reshape. I managed to recover though.
Since then I always do a raid-check before starting any changes.
Good luck and thanks for the story so far.
Alex.
========================================================================
# _ __ _ __ http://www.nagilum.org/ \n icq://69646724 #
# / |/ /__ ____ _(_) /_ ____ _ nagilum@nagilum.org \n +491776461165 #
# / / _ `/ _ `/ / / // / ' \ Amiga (68k/PPC): AOS/NetBSD/Linux #
# /_/|_/\_,_/\_, /_/_/\_,_/_/_/_/ Mac (PPC): MacOS-X / NetBSD /Linux #
# /___/ x86: FreeBSD/Linux/Solaris/Win2k ARM9: EPOC EV6 #
========================================================================
----------------------------------------------------------------
cakebox.homeunix.net - all the machine one needs..
next prev parent reply other threads:[~2010-09-28 15:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-26 7:27 Accidental grow before add Mike Hartman
2010-09-26 9:39 ` Mike Hartman
2010-09-26 9:54 ` Mike Hartman
2010-09-26 9:59 ` Mikael Abrahamsson
2010-09-26 10:18 ` Mike Hartman
2010-09-26 10:38 ` Robin Hill
2010-09-26 19:34 ` Mike Hartman
2010-09-26 21:22 ` Robin Hill
2010-09-27 8:11 ` Jon Hardcastle
2010-09-27 9:05 ` Mike Hartman
2010-09-28 15:14 ` Nagilum [this message]
2010-10-05 5:18 ` Neil Brown
2010-09-30 16:13 ` Mike Hartman
2010-10-05 6:24 ` Neil Brown
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100928171451.27293d0o1kotcfi8@cakebox.homeunix.net \
--to=nagilum@nagilum.org \
--cc=Jon@ehardcastle.com \
--cc=linux-raid@vger.kernel.org \
--cc=mike@hartmanipulation.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).