From: "Adam Kropelin" <akropel1@rochester.rr.com>
To: "Neil Brown" <neilb@suse.de>
Cc: <linux-raid@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
"Steinar H. Gunderson" <sgunderson@bigfoot.com>
Subject: Re: [PATCH 000 of 5] md: Introduction
Date: Mon, 23 Jan 2006 18:02:56 -0500 [thread overview]
Message-ID: <0ad101c62071$261ebde0$03c8a8c0@kroptech.com> (raw)
In-Reply-To: 17364.3266.29943.914861@cse.unsw.edu.au
Neil Brown wrote:
> On Saturday January 21, akropel1@rochester.rr.com wrote:
>> On the first try I neglected to read the directions and increased the
>> number of devices first (which worked) and then attempted to add the
>> physical device (which didn't work; at least not the way I intended).
>
> Thanks, this is exactly the sort of feedback I was hoping for - people
> testing thing that I didn't think to...
>
>> mdadm --create -l5 -n3 /dev/md0 /dev/sda /dev/sdb /dev/sdc
>>
>> md0 : active raid5 sda[0] sdc[2] sdb[1]
>> 2097024 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]
>>
>> mdadm --grow -n4 /dev/md0
>>
>> md0 : active raid5 sda[0] sdc[2] sdb[1]
>> 3145536 blocks level 5, 64k chunk, algorithm 2 [4/3] [UUU_]
>
> I assume that no "resync" started at this point? It should have done.
Actually, it did start a resync. Sorry, I should have mentioned that. I
waited until the resync completed before I issued the 'mdadm --add'
command.
>> md0 : active raid5 sdd[3] sdc[2] sdb[1] sda[0]
>> 2097024 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
>> ...should this be... --> [4/3]
>> [UUU_] perhaps?
>
> Well, part of the array is "4/4 UUUU" and part is "3/3 UUU". How do
> you represent that? I think "4/4 UUUU" is best.
I see your point. I was expecting some indication that that my array was
vulnerable and that the new disk was not fully utilized yet. I guess the
resync in progress indicator is sufficient.
>> My final test was a repeat of #2, but with data actively being
>> written
>> to the array during the reshape (the previous tests were on an idle,
>> unmounted array). This one failed pretty hard, with several processes
>> ending up in the D state.
>
> Hmmm... I tried similar things but didn't get this deadlock. Somehow
> the fact that mdadm is holding the reconfig_sem semaphore means that
> some IO cannot proceed and so mdadm cannot grab and resize all the
> stripe heads... I'll have to look more deeply into this.
For what it's worth, I'm using the Buslogic SCSI driver for the disks in
the array.
>> I'm happy to do more tests. It's easy to conjur up virtual disks and
>> load them with irrelevant data (like kernel trees ;)
>
> Great. I'll probably be putting out a new patch set late this week
> or early next. Hopefully it will fix the issues you can found and you
> can try it again..
Looking forward to it...
--Adam
next prev parent reply other threads:[~2006-01-23 23:02 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-17 6:56 [PATCH 000 of 5] md: Introduction NeilBrown
2006-01-17 6:56 ` [PATCH 001 of 5] md: Split disks array out of raid5 conf structure so it is easier to grow NeilBrown
2006-01-17 14:37 ` John Stoffel
2006-01-19 0:26 ` Neil Brown
2006-01-21 3:37 ` John Stoffel
2006-01-22 22:57 ` Neil Brown
2006-01-17 6:56 ` [PATCH 002 of 5] md: Allow stripes to be expanded in preparation for expanding an array NeilBrown
2006-01-17 6:56 ` [PATCH 003 of 5] md: Infrastructure to allow normal IO to continue while array is expanding NeilBrown
2006-01-17 6:56 ` [PATCH 004 of 5] md: Core of raid5 resize process NeilBrown
2006-01-17 6:56 ` [PATCH 005 of 5] md: Final stages of raid5 expand code NeilBrown
2006-01-17 9:55 ` Sander
2006-01-19 0:32 ` Neil Brown
2006-01-17 8:17 ` [PATCH 000 of 5] md: Introduction Michael Tokarev
2006-01-17 9:50 ` Sander
2006-01-17 11:26 ` Michael Tokarev
2006-01-17 14:03 ` Kyle Moffett
2006-01-19 0:28 ` Neil Brown
2006-01-17 16:08 ` Ross Vandegrift
2006-01-17 18:12 ` Michael Tokarev
2006-01-18 8:14 ` Sander
2006-01-18 9:03 ` Alan Cox
2006-01-19 0:22 ` Neil Brown
2006-01-19 9:01 ` Jakob Oestergaard
2006-01-17 22:38 ` Phillip Susi
2006-01-17 22:57 ` Neil Brown
2006-01-17 14:10 ` Steinar H. Gunderson
2006-01-22 4:42 ` Adam Kropelin
2006-01-22 22:52 ` Neil Brown
2006-01-23 23:02 ` Adam Kropelin [this message]
2006-01-23 1:08 ` John Hendrikx
2006-01-23 1:25 ` Neil Brown
2006-01-23 1:54 ` Kyle Moffett
2006-01-17 21:38 Lincoln Dale (ltd)
2006-01-18 13:27 ` Jan Engelhardt
2006-01-18 23:19 ` Neil Brown
2006-01-19 15:33 ` Mark Hahn
2006-01-19 20:12 ` Jan Engelhardt
2006-01-19 21:22 ` Lars Marowsky-Bree
2006-01-19 22:17 ` Phillip Susi
2006-01-19 22:32 ` Neil Brown
2006-01-19 23:26 ` Phillip Susi
2006-01-19 23:43 ` Neil Brown
2006-01-20 2:17 ` Phillip Susi
2006-01-20 10:53 ` Lars Marowsky-Bree
2006-01-20 12:06 ` Jens Axboe
2006-01-20 18:38 ` Heinz Mauelshagen
2006-01-20 22:09 ` Lars Marowsky-Bree
2006-01-21 0:06 ` Heinz Mauelshagen
2006-01-20 18:41 ` Heinz Mauelshagen
2006-01-20 17:29 ` Ross Vandegrift
2006-01-20 18:36 ` Heinz Mauelshagen
2006-01-20 22:57 ` Lars Marowsky-Bree
2006-01-21 0:01 ` Heinz Mauelshagen
2006-01-21 0:03 ` Lars Marowsky-Bree
2006-01-21 0:08 ` Heinz Mauelshagen
2006-01-21 0:13 ` Lars Marowsky-Bree
2006-01-23 9:44 ` Heinz Mauelshagen
2006-01-23 10:26 ` Lars Marowsky-Bree
2006-01-23 10:38 ` Heinz Mauelshagen
2006-01-23 10:45 ` Lars Marowsky-Bree
2006-01-23 11:00 ` Heinz Mauelshagen
2006-01-23 12:54 ` Ville Herva
2006-01-23 13:00 ` Steinar H. Gunderson
2006-01-23 13:54 ` Heinz Mauelshagen
2006-01-23 17:33 ` Ville Herva
2006-01-24 2:02 ` Phillip Susi
2006-01-20 16:48 Hubert Tonneau
2006-01-20 17:01 Hubert Tonneau
2006-01-20 16:15 ` Christoph Hellwig
2006-01-22 6:45 ` Herbert Poetzl
2006-01-20 18:05 Hubert Tonneau
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