[linux-lvm] Removing disk from raid LVM
libor.klepac at bcom.cz
Wed Mar 11 13:05:37 UTC 2015
On Út 10. března 2015 10:05:38 John Stoffel wrote:
> Libor> web have 4x3TB disks in LVM for backups and I setup per
> Libor> customer/per "task" LV type raid5 on it.
> Can you post the configuration details please, since they do matter.
> It would seem to me, that it would be better to use 'md' to create the
> underlying RAID5 device, and then use LVM on top of that /dev/md0 to
> create the customer LV(s) as needed.
I used mdraid everytime before (in fact, OS is on another disks on mdraid). But i
really loved idea/flexibility of raid in LVM and wanted to try it.
> Libor> Last week, smartd started to alarm us, that one of the disk
> Libor> will soon go away.
> Libor> So we shut down the computer, replaced disk and then i used
> Libor> vgcfgrestore on new disk to restore metadata.
> You should have shutdown the system, added in a new disk, and then
> rebooted the system. At that point you would add the new disk into
> the RAID5, and then fail the dying disk. It would be transparent to
> the LVM setup and be much safer.
I see, but there is no physical space for extra disk. Maybe external disk should
do the trick, but it would take hours to migrate data and server is in remote
> I'd also strongly advise you to get RAID6 setup and have a hot spare
> also setup, so that you don't have this type of issue in the future.
> Libor> Result was, that some LVs came up with damaged filesystem, some
> Libor> didn't came up at all with messages like (one of rimage and
> Libor> rmeta was "wrong", when i used KVPM util, it was type "virtual"
> This sounds very much like you just lost a bunch of data, which RAID5
> shouldn't do. So please post the details of your setup, starting at
> the disk level and moving up the stack to the filesystem(s) you have
> mounted for backups. We don't need the customer names, etc, just the
> details of the system.
System is Dell T20.
Backup disks are connected over
00:1f.2 SATA controller: Intel Corporation Lynx Point 6-port SATA Controller 1
[AHCI mode] (rev 04)
System disks are connected over
04:00.0 SATA controller: Marvell Technology Group Ltd. 88SE9230 PCIe SATA
6Gb/s Controller (rev 10)
First three are 3TB sata discs, 3,5'', 7200RPM
[0:0:0:0] disk ATA TOSHIBA MG03ACA3 n/a /dev/sda
[1:0:0:0] disk ATA ST3000NM0033-9ZM n/a /dev/sdb
[2:0:0:0] disk ATA ST3000NM0033-9ZM n/a /dev/sdg
[3:0:0:0] disk ATA TOSHIBA MG03ACA3 n/a /dev/sdd
Remaining two are 500GB 2,5'' disks for system
[6:0:0:0] disk ATA ST9500620NS n/a /dev/sde
[8:0:0:0] disk ATA ST9500620NS n/a /dev/sdf
System is on mdraid (raid1) + LVM
On top of LVs, we use ext4 for OS and XFS for backup/customer disks.
> Also, which version of lvm, md, linux kernel, etc are you using? The
> more details the better.
It's Debian Wheezy, with kernel 3.14(.14)
System LVM is
LVM version: 2.02.95(2) (2012-03-06)
Library version: 1.02.74 (2012-03-06)
Driver version: 4.27.0
I also use another copy of lvm, for raid operations (creating LV, extending LVs,
show progress of resync) ...
LVM version: 2.02.104(2) (2013-11-13)
Library version: 1.02.83 (2013-11-13)
Driver version: 4.27.0
Should the problem be, that VG/LVs are first constructed using system old utils?
I think, i could upgrade whole system to Debian Jessie as last resort operation.
This should bring kernel to version 3.16 and lvm to 2.02.111
Thanks for your reply
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> linux-lvm at redhat.com
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
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