pvmoveを利用して物理ディスクのデータを別の物理ディスクへオンラインで移設する
January 11, 2014
AWSとLVMを利用することによって、オンラインで
EBSをアタッチして、pvmoveでデータを新しいEBSへ移行し
元のEBSを切り離すことができる。
参考
redhat カスタマーポータル - 6 5.4. 論理ボリュームからのディスクの削除
pvmoveは同一VG内の空きPVに移動するのか。ということは旧ディスクから新ディスクへの移行は 1.新ディスクをLVMフォーマットで作成して 2.新ディスクをPV化して 3.旧ディスクがアサインされいるVGにvgexendでPVを追加して 4.pvmoveか
— kenjiskywalker (@kenjiskywalker) 2014, 1月 7pvremoveするときはVGにアサインされているからまずvgreduceで対象のPVを切り離してからpvremoveか。当たり前っちゃあ当たり前か
— kenjiskywalker (@kenjiskywalker) 2014, 1月 7とのことです。
検証環境
- ルートパーティション
/dev/xvda1 16GB
- EBS
/dev/xvdb 64GB EBS
- RAID0用EBS
/dev/xvdc 16GB EBS
/dev/xvdd 16GB EBS
/dev/xvde 16GB EBS
/dev/xvdf 16GB EBS
xvdbに既存データが存在していており
そのデータをmd127に移設する。
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# fdisk -l
Disk /dev/xvda1: 17.2 GB, 17179869184 bytes
255 heads, 63 sectors/track, 2088 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/xvde: 17.2 GB, 17179869184 bytes
255 heads, 63 sectors/track, 2088 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/xvdd: 17.2 GB, 17179869184 bytes
255 heads, 63 sectors/track, 2088 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/xvdc: 17.2 GB, 17179869184 bytes
255 heads, 63 sectors/track, 2088 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/xvdb: 68.7 GB, 68719476736 bytes
255 heads, 63 sectors/track, 8354 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
Disk /dev/xvdf: 17.2 GB, 17179869184 bytes
255 heads, 63 sectors/track, 2088 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
[root@lvm-test-server ~]#
EBS x4をまとめてRAID0を組む
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# yes | mdadm --create /dev/md127 --level=0 --raid-devices=4 /dev/xvd[cdef]
mdadm: /dev/xvdc appears to be part of a raid array:
level=raid0 devices=4 ctime=Tue Jan 7 09:36:58 2014
mdadm: /dev/xvdd appears to be part of a raid array:
level=raid0 devices=4 ctime=Tue Jan 7 09:36:58 2014
mdadm: /dev/xvdf appears to be part of a raid array:
level=raid0 devices=4 ctime=Tue Jan 7 09:36:58 2014
Continue creating array? mdadm: Defaulting to version 1.2 metadata
mdadm: array /dev/md127 started.
[root@lvm-test-server ~]#
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# cat /proc/mdstat
Personalities : [raid0]
md127 : active raid0 xvdf[3] xvde[2] xvdd[1] xvdc[0]
67106816 blocks super 1.2 512k chunks
unused devices: <none>
[root@lvm-test-server ~]#
既存のVG（引っ越し元のディスクが入っているVG）にRAID0のPVをアサイン
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# pvcreate /dev/md127
Physical volume "/dev/md127" successfully created
[root@lvm-test-server ~]#
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# vgdisplay
--- Volume group ---
VG Name vgrp0
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 2
Act PV 2
VG Size 63.99 GiB
PE Size 4.00 MiB
Total PE 16381
Alloc PE / Size 0 / 0
Free PE / Size 16381 / 63.99 GiB
VG UUID j4hcOI-hsYy-j8jL-Dnp7-wa44-ue4c-ZlMi5m
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# vgextend vgrp0 /dev/md127
Volume group "vgrp0" successfully extended
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# vgdisplay
--- Volume group ---
VG Name vgrp0
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 127.99 GiB
PE Size 4.00 MiB
Total PE 32766
Alloc PE / Size 16383 / 64.00 GiB
Free PE / Size 16383 / 64.00 GiB
VG UUID x6y3NX-WNwZ-8pOj-Ez0S-U7r4-fice-9CljNP
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# pvs -o+pv_used
PV VG Fmt Attr PSize PFree Used
/dev/md127 vgrp0 lvm2 a-- 64.00g 0 64.00g
/dev/xvdb1 vgrp0 lvm2 a-- 64.00g 0 64.00g
[root@lvm-test-server ~]#
[root@lvm-test-server ~]#
この時点でxvdb1(64GB)とmd127(128GB)がVGにアサインされている。
PVからPVへデータを移行
[root@lvm-test-server ~]# pvmove /dev/xvdb1
/dev/xvdb1: Moved: 0.0%
/dev/xvdb1: Moved: 0.4%
/dev/xvdb1: Moved: 0.7%
/dev/xvdb1: Moved: 1.1%
/dev/xvdb1: Moved: 1.4%
/dev/xvdb1: Moved: 1.8%
/dev/xvdb1: Moved: 2.1%
/dev/xvdb1: Moved: 2.5%
/dev/xvdb1: Moved: 2.8%
/dev/xvdb1: Moved: 3.2%
...
/dev/xvdb1: Moved: 99.1%
/dev/xvdb1: Moved: 99.5%
/dev/xvdb1: Moved: 99.8%
/dev/xvdb1: Moved: 100.0%
Found volume group "vgrp0"
Found volume group "vgrp0"
Loading vgrp0-lvol0 table (253:0)
Loading vgrp0-pvmove0 table (253:2)
Suspending vgrp0-lvol0 (253:0) with device flush
Suspending vgrp0-pvmove0 (253:2) with device flush
Found volume group "vgrp0"
Resuming vgrp0-pvmove0 (253:2)
Found volume group "vgrp0"
Resuming vgrp0-lvol0 (253:0)
Found volume group "vgrp0"
Removing vgrp0-pvmove0 (253:2)
Removing temporary pvmove LV
Writing out final volume group after pvmove
Creating volume group backup "/etc/lvm/backup/vgrp0" (seqno 6).
[root@lvm-test-server ~]#
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# pvs -o+pv_used
PV VG Fmt Attr PSize PFree Used
/dev/md127 vgrp0 lvm2 a-- 64.00g 0 64.00g
/dev/xvdb1 vgrp0 lvm2 a-- 64.00g 64.00g 0
[root@lvm-test-server ~]#
PFreeになっていることを確認
[root@lvm-test-server ~]# vgdisplay
--- Volume group ---
VG Name vgrp0
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 6
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 2
Act PV 2
VG Size 127.99 GiB
PE Size 4.00 MiB
Total PE 32766
Alloc PE / Size 16383 / 64.00 GiB
Free PE / Size 16383 / 64.00 GiB
VG UUID x6y3NX-WNwZ-8pOj-Ez0S-U7r4-fice-9CljNP
[root@lvm-test-server ~]#
xvdb1をVGから切り離す
[root@lvm-test-server ~]# vgreduce vgrp0 /dev/xvdb1
Removed "/dev/xvdb1" from volume group "vgrp0"
[root@lvm-test-server ~]#
[root@lvm-test-server ~]#
[root@lvm-test-server ~]# vgdisplay
--- Volume group ---
VG Name vgrp0
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 7
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 1
Act PV 1
VG Size 64.00 GiB
PE Size 4.00 MiB
Total PE 16383
Alloc PE / Size 16383 / 64.00 GiB
Free PE / Size 0 / 0
VG UUID x6y3NX-WNwZ-8pOj-Ez0S-U7r4-fice-9CljNP
[root@lvm-test-server ~]#
Allocサイズが変わっていることを確認。
この後はPVを削除してEBSをデタッチすればデータの移設が完了します。