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xibo
Apprentice
Joined: 21 Aug 2007
Posts: 152
Location: moving between kubuntu and ubuntu kde edition
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 Posted: Sun Dec 20, 2009 9:38 am Post subject: mdadm problem adding disc to raid 6 |
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hello,
i m trying to expand a raid 6 array by a disc. i partitioned it to have a single partition of type 0xfd, like all already present discs of the array and have the same partition size, and successfully added the new partition to the array as a spare. however, when i try to grow the array, mdadm aborts saying
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mdadm --grow --raid-devices=7 (it's having 6 active discs plus 1 spare)
mdadm: this change will reduce the size of the array.
use --grow --array-size first to truncate array.
e.g. mdadm --grow /dev/md0 --array-size 588832384
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i tryed reducing array-size by like 30% and tryed growing again, but it still doesn't work.
maybe usefull information:
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mdadm --detail
/dev/md0:
Version : 0.90
Creation Time : Sun Apr 26 22:15:17 2009
Raid Level : raid6
Array Size : 3907039744 (3726.04 GiB 4000.81 GB)
Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
Raid Devices : 6
Total Devices : 7
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Sun Dec 20 10:28:15 2009
State : clean
Active Devices : 6
Working Devices : 7
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 64K
UUID : 1264f470:e88147ab:3e948e8a:28f597c6
Events : 0.686657
Number Major Minor RaidDevice State
0 8 113 0 active sync /dev/sdh1
1 8 129 1 active sync /dev/sdi1
2 8 81 2 active sync /dev/sdf1
3 8 49 3 active sync /dev/sdd1
4 8 65 4 active sync /dev/sde1
5 8 97 5 active sync /dev/sdg1
6 8 33 - spare /dev/sdc1
cat /proc/mdstat
Personalities : [raid1] [raid6] [raid5] [raid4]
md0 : active raid6 sdc1[6](S) sdi1[1] sdh1[0] sdg1[5] sde1[4] sdf1[2] sdd1[3]
3907039744 blocks level 6, 64k chunk, algorithm 2 [6/6] [UUUUUU]
unused devices: <none>
mdadm --version
mdadm - v3.1.1 - 19th November 2009
cat /proc/version
Linux version 2.6.32.2 (root@ip002) (gcc version 4.4.2 (Gentoo 4.4.2 p1.0) ) #3 SMP Sun Dec 20 09:36:25 CET 2009
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richard.scott
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Joined: 19 May 2003
Posts: 1497
Location: Oxfordshire, UK
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| Posted: Sun Dec 20, 2009 10:07 pm Post subject: |
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does your kernel have the support option activated to grow a raid6 device?
Try this:
| Code: | | mdadm --grow /dev/md0 --size=max |
...and see if it works. |
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xibo
Apprentice
Joined: 21 Aug 2007
Posts: 152
Location: moving between kubuntu and ubuntu kde edition
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| Posted: Sun Dec 20, 2009 11:37 pm Post subject: |
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| richard.scott wrote: | Try this:
| Code: | | mdadm --grow /dev/md0 --size=max |
...and see if it works. |
the command successfully terminates, but it only resets the amount of blocks used of each device ( instead of the number of active devices ).
| richard.scott wrote: | | does your kernel have the support option activated to grow a raid6 device? |
i don't have the option availible in menuconfig, nor is disabled in .config . i remember having seen it in the past though... did it become too unstable or do i need a special patch or something like that? ( i thought it was integrated to raid6 support now )
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cat /usr/src/linux/.config | grep CONFIG_MD --after-context=25
CONFIG_MD=y
CONFIG_BLK_DEV_MD=y
CONFIG_MD_AUTODETECT=y
# CONFIG_MD_LINEAR is not set
# CONFIG_MD_RAID0 is not set
CONFIG_MD_RAID1=y
# CONFIG_MD_RAID10 is not set
CONFIG_MD_RAID456=y
# CONFIG_MULTICORE_RAID456 is not set
CONFIG_MD_RAID6_PQ=y
# CONFIG_ASYNC_RAID6_TEST is not set
CONFIG_MD_MULTIPATH=m
# CONFIG_MD_FAULTY is not set
CONFIG_BLK_DEV_DM=m
# CONFIG_DM_DEBUG is not set
CONFIG_DM_CRYPT=m
# CONFIG_DM_SNAPSHOT is not set
CONFIG_DM_MIRROR=m
CONFIG_DM_LOG_USERSPACE=m
CONFIG_DM_ZERO=m
CONFIG_DM_MULTIPATH=m
CONFIG_DM_MULTIPATH_QL=m
CONFIG_DM_MULTIPATH_ST=m
CONFIG_DM_DELAY=m
# CONFIG_DM_UEVENT is not set
# CONFIG_FUSION is not set
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richard.scott
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Joined: 19 May 2003
Posts: 1497
Location: Oxfordshire, UK
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| Posted: Mon Dec 21, 2009 8:05 am Post subject: |
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I've just re-read this (now I'm awake):
| Code: | Number Major Minor RaidDevice State
0 8 113 0 active sync /dev/sdh1
1 8 129 1 active sync /dev/sdi1
2 8 81 2 active sync /dev/sdf1
3 8 49 3 active sync /dev/sdd1
4 8 65 4 active sync /dev/sde1
5 8 97 5 active sync /dev/sdg1
6 8 33 - spare /dev/sdc1 |
You have 6 disks, and a spare... this means that you have 4 usable disks, two for parity and 1 spare. totalling the 7 you have in your system.
Your array looks to be at its max size, as you can't use a spare as its a spare.
Rich |
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xibo
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Joined: 21 Aug 2007
Posts: 152
Location: moving between kubuntu and ubuntu kde edition
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| Posted: Mon Dec 21, 2009 12:40 pm Post subject: |
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| That's what I want to change: reshape the array to have 5 data and 2 parity devices... |
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richard.scott
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Joined: 19 May 2003
Posts: 1497
Location: Oxfordshire, UK
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| Posted: Mon Dec 21, 2009 1:08 pm Post subject: |
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What you had before should have worked:
| Code: | | mdadm --grow /dev/md0 --raid-disks=7 |
I found it on this page:
http://www.kolbu.com/2007/01/10/growing-raid5-sets-in-ubuntu/
Did you remember to include the "/dev/md0" as you haven't listed that in your output?
Rich |
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xibo
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Posts: 152
Location: moving between kubuntu and ubuntu kde edition
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