Re: Removing disk from raid LVM

Premchand Gupta <gpremchand@gmail.com> · Thu, 12 Mar 2015 04:42:24 +0530

Hi ,
if software raid is configure over the lvm, then follow below step.
step 1) fail and remove the device from raid 5 with command mdamd
step 2) removed disk form lv, vg then pv
step 3) delete it from system with echo command

Thanks & Regards

Premchand S. Gupta
09820314487

On Mon, Mar 9, 2015 at 4:51 PM, Libor Klepáč <libor.klepac@bcom.cz> wrote:

Hello,
web have 4x3TB disks in LVM for backups and I setup per customer/per "task" LV type raid5 on it.
Last week, smartd started to alarm us, that one of the disk will soon go away.

So we shut down the computer, replaced disk and then i used vgcfgrestore on new disk to restore metadata.
Result was, that some LVs came up with damaged filesystem, some didn't came up at all with messages like (one of rimage and rmeta was "wrong", when i used KVPM util, it was type "virtual"
----
[123995.826650] mdX: bitmap initialized from disk: read 4 pages, set 1 of 98312 bits
[124071.037501] device-mapper: raid: Failed to read superblock of device at position 2
[124071.055473] device-mapper: raid: New device injected into existing array without 'rebuild' parameter specified
[124071.055969] device-mapper: table: 253:83: raid: Unable to assemble array: Invalid superblocks
[124071.056432] device-mapper: ioctl: error adding target to table
----
After that, i tried several combinations of
lvconvert --repair 
and
lvchange -ay --resync

Without success. So i saved some data and than created new empty LV's and started backups from scratch.

Today, smartd alerted on another disk.
So how can i safely remove disk from VG?
I tried to simulate it on VM

echo 1 > /sys/block/sde/device/delete
vgreduce -ff vgPecDisk2 /dev/sde #doesn't allow me to remove
vgreduce --removemissing vgPecDisk2 #doesn't allow me to remove
vgreduce --removemissing --force vgPecDisk2 #works, alerts me about rimage and rmeta LVS

vgchange -ay vgPecDisk2 #works but LV isn't active, only rimage and rmeta LV show up.

So how to safely remove soon-to-be-bad-drive and insert new drive to array?
Server has no more physical space for new drive, so we cannot use pvmove.

Server is debian wheezy, but kernel is 2.6.14.
Lvm is in version 2.02.95-8 , but i have another copy i use for raid operations, which is in version 2.02.104

With regards

Libor

_______________________________________________

linux-lvm mailing list

linux-lvm@redhat.com

https://www.redhat.com/mailman/listinfo/linux-lvm

read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/