KVMでHDDを追加する時のメモ
CentOSやRHL上で動かすKVMのHDD容量を追加する時の手順。
イメージファイルを増量
まずKVMを動かしているホスト機で、増やしたいVMのイメージを追加する。
$ qemu-img resize vmtest.img +10G
※vmtestというイメージに10G追加したい場合
fdiskでパーティションを増量
VM内にログインし、fdiskコマンドでdisk容量が増えているか確認。
$ssh vmtest
$fdisk -l
Disk /dev/vda: 21.5 GB, 21474836480 bytes
16 heads, 63 sectors/track, 41610 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000e180d
Device Boot Start End Blocks Id System
/dev/vda1 * 3 1018 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/vda2 1018 20806 9972736 8e Linux LVM
Partition 2 does not end on cylinder boundary.
この場合は元が10Gでさらに10G足したので無事増えているので、/dev/vdaのパーティションを区切ります。
$fdisk /dev/vda
WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
switch off the mode (command 'c') and change display units to
sectors (command 'u').
パーティション一覧を確認します。
Command (m for help): p
Disk /dev/vda: 21.5 GB, 21474836480 bytes
16 heads, 63 sectors/track, 41610 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000e180d
Device Boot Start End Blocks Id System
/dev/vda1 * 3 1018 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/vda2 1018 20806 9972736 8e Linux LVM
Partition 2 does not end on cylinder boundary.
パーティションが２つあるので、３つ目に新たに追加します。
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 3
次にどこのcylinderから始めるかと聞かれるので、この場合は２つ目の最後20806から+1した20807を入力します。
First cylinder (1-41610, default 1): 20807
Last cylinder, +cylinders or +size{K,M,G} (20807-41610, default 41610): 41610
ラストはデフォルトの最後まででOKです。
またｐコマンドで無事追加されたのを確認します。
Command (m for help): p
Disk /dev/vda: 21.5 GB, 21474836480 bytes
16 heads, 63 sectors/track, 41610 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000e180d
Device Boot Start End Blocks Id System
/dev/vda1 * 3 1018 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/vda2 1018 20806 9972736 8e Linux LVM
Partition 2 does not end on cylinder boundary.
/dev/vda3 20807 41610 10485216 83 Linux
３つ目の追加したパーティションもLVMにします。
Command (m for help): t
Partition number (1-4): 3
Hex code (type L to list codes): 8e
Changed system type of partition 3 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/vda: 21.5 GB, 21474836480 bytes
16 heads, 63 sectors/track, 41610 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000e180d
Device Boot Start End Blocks Id System
/dev/vda1 * 3 1018 512000 83 Linux
Partition 1 does not end on cylinder boundary.
/dev/vda2 1018 20806 9972736 8e Linux LVM
Partition 2 does not end on cylinder boundary.
/dev/vda3 20807 41610 10485216 8e Linux LVM
無事変わったのを確認したらセーブして再起動します。
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
$reboot -h now
追加パーティションを物理Vol化＆論理Vol拡張
再度VMに入り、追加パーティションを物理ボリューム化します。
$ssh vmtest
$pvcreate /dev/vda3
Physical volume "/dev/vda3" successfully created
追加されたか確認
$pvdisplay
--- Physical volume ---
PV Name /dev/vda2
VG Name vg_vmtestimg1
PV Size 9.51 GiB / not usable 3.00 MiB
Allocatable yes (but full)
PE Size 4.00 MiB
Total PE 2434
Free PE 0
Allocated PE 2434
PV UUID XCTuf9-07iA-iwnO-CAh0-QT0u-Temb-xymCGY
"/dev/vda3" is a new physical volume of "10.00 GiB"
--- NEW Physical volume ---
PV Name /dev/vda3
VG Name
PV Size 10.00 GiB
Allocatable NO
PE Size 0
Total PE 0
Free PE 0
Allocated PE 0
PV UUID EZN6pR-s8OX-SY1f-faQq-y7T2-VJAe-cnPxgB
VG名を取得
$vgdisplay
--- Volume group ---
VG Name vg_vmtestimg1
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 9.51 GiB
PE Size 4.00 MiB
Total PE 2434
Alloc PE / Size 2434 / 9.51 GiB
Free PE / Size 0 / 0
VG UUID Wfi6Mw-tK8R-SZmH-xOBm-mmuq-1bmL-hFn40B
VGを拡張&確認
$vgextend vg_vmtestimg1 /dev/vda3
Volume group "vg_vmtestimg1" successfully extended
$vgdisplay
--- Volume group ---
VG Name vg_vmtestimg1
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 2
Act PV 2
VG Size 19.50 GiB
PE Size 4.00 MiB
Total PE 4993
Alloc PE / Size 2434 / 9.51 GiB
Free PE / Size 2559 / 10.00 GiB
VG UUID Wfi6Mw-tK8R-SZmH-xOBm-mmuq-1bmL-hFn40B
論理ボリューム名を確認
$lvdisplay
--- Logical volume ---
LV Path /dev/vg_vmtestimg1/lv_root
LV Name lv_root
VG Name vg_vmtestimg1
LV UUID JtIgxT-mBPj-LO1H-Uc9u-13t3-1gwX-Y11UUR
LV Write Access read/write
LV Creation host, time dev-pfortune-img1, 2015-09-08 07:16:27 +0900
LV Status available
# open 1
LV Size 8.51 GiB
Current LE 2178
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:0
論理ボリュームを追加
$lvextend -l +100%FREE /dev/vg_vmtestimg1/lv_root
Size of logical volume vg_vmtestimg1/lv_root changed from 8.51 GiB (2178 extents) to 18.50 GiB (4737 extents).
Logical volume lv_root successfully resized
$resize2fs /dev/vg_vmtestimg1/lv_root
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vg_vmtestimg1/lv_root is mounted on /; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 2
Performing an on-line resize of /dev/vg_vmtestimg1/lv_root to 4850688 (4k) blocks.
The filesystem on /dev/vg_vmtestimg1/lv_root is now 4850688 blocks long.
centos7の場合は resize2fsではなく、xfs_growfsで拡張を行う
$xfs_growfs /dev/vg_vmtestimg1/lv_root
容量をdfコマンドで確認
$df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/mapper/vg_vmtestimg1-lv_root
18968780 1115892 16889024 7% /
tmpfs 961100 0 961100 0% /dev/shm
/dev/vda1 487652 73701 388351 16% /boot
追加されていれば無事終了です。
