From: Roman Mamedov <rm@romanrm.ru>
To: linux-raid@vger.kernel.org
Subject: Can't reshape RAID1 to RAID5 due to chunk size
Date: Wed, 12 Sep 2012 10:59:56 +0600 [thread overview]
Message-ID: <20120912105956.155f5d5e@natsu> (raw)
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Hello,
# mdadm --detail /dev/md1
/dev/md1:
Version : 1.2
Creation Time : Fri May 27 09:50:54 2011
Raid Level : raid1
Array Size : 488372863 (465.75 GiB 500.09 GB)
Used Dev Size : 488372863 (465.75 GiB 500.09 GB)
Raid Devices : 2
Total Devices : 3
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Wed Sep 12 10:54:33 2012
State : active
Active Devices : 2
Working Devices : 3
Failed Devices : 0
Spare Devices : 1
Name : avdeb:1 (local to host avdeb)
UUID : e29a222d:e6245302:5ff3f834:ad471a01
Events : 26
Number Major Minor RaidDevice State
0 8 82 0 active sync /dev/sdf2
1 8 34 1 active sync /dev/sdc2
2 8 50 - spare /dev/sdd2
# mdadm --grow /dev/md1 --chunk=64K --level=5 --raid-devices=3
mdadm: New chunk size does not divide component size
-----
Shouldn't mdadm be able to figure out a way to somehow proceed in this case? :)
So what if it does not divide, I am increasing the array size by 33%, it
has plenty of new space, why not leave a bit of it in the end of all devices so
the chunk size does divide...
Also I heard of cases (on #linux-raid IRC, I think) when people reshaped like
this without specifying the chunk size explicitly, and ended up with something
like a 4K chunk, which is certainly less than optimal.
--
With respect,
Roman
~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Stallman had a printer,
with code he could not see.
So he began to tinker,
and set the software free."
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next reply other threads:[~2012-09-12 4:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-12 4:59 Roman Mamedov [this message]
2012-09-19 6:20 ` Can't reshape RAID1 to RAID5 due to chunk size NeilBrown
2012-09-19 7:46 ` Roman Mamedov
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