CentOS Logical Volumes Management
PREPARATORY STEPS
- I did shut down the virtual host
- I created 4 virtual hard disk drives big 10GB each
- I attached them to a virtual SCSI controller of my virtual host
- I powered on the virtual host
AT BOOT
Now these messages ad displayed at boot (dmesg):
... hv_vmbus: registering driver hv_storvsc scsi2 : storvsc_host_t scsi 2:0:0:0: Direct-Access Msft Virtual Disk 1.0 PQ: 0 ANSI: 4 scsi3 : storvsc_host_t scsi 3:0:0:0: Direct-Access Msft Virtual Disk 1.0 PQ: 0 ANSI: 4 scsi 3:0:0:2: Direct-Access Msft Virtual Disk 1.0 PQ: 0 ANSI: 4 scsi 3:0:0:1: Direct-Access Msft Virtual Disk 1.0 PQ: 0 ANSI: 4 scsi 3:0:0:3: Direct-Access Msft Virtual Disk 1.0 PQ: 0 ANSI: 4 sd 2:0:0:0: [sda] 266338304 512-byte logical blocks: (136 GB/127 GiB) sd 2:0:0:0: [sda] Write Protect is off sd 2:0:0:0: [sda] Mode Sense: 0f 00 00 00 sd 3:0:0:0: [sdb] 20971520 512-byte logical blocks: (10.7 GB/10.0 GiB) sd 3:0:0:2: [sdc] 20971520 512-byte logical blocks: (10.7 GB/10.0 GiB) sd 3:0:0:0: [sdb] Write Protect is off sd 3:0:0:0: [sdb] Mode Sense: 0f 00 00 00 sd 3:0:0:2: [sdc] Write Protect is off sd 3:0:0:2: [sdc] Mode Sense: 0f 00 00 00 sd 2:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA sd 3:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA sd 3:0:0:2: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA sda: sdb: sda1 sda2 sdc: sd 3:0:0:1: [sdd] 20971520 512-byte logical blocks: (10.7 GB/10.0 GiB) sd 3:0:0:1: [sdd] Write Protect is off sd 3:0:0:1: [sdd] Mode Sense: 0f 00 00 00 sd 2:0:0:0: [sda] Attached SCSI disk sd 3:0:0:1: [sdd] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA sd 3:0:0:3: [sde] 20971520 512-byte logical blocks: (10.7 GB/10.0 GiB) sd 3:0:0:3: [sde] Write Protect is off sd 3:0:0:3: [sde] Mode Sense: 0f 00 00 00 sd 3:0:0:3: [sde] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA sdd: sde: unknown partition table sd 3:0:0:0: [sdb] Attached SCSI disk unknown partition table sd 3:0:0:2: [sdc] Attached SCSI disk unknown partition table unknown partition table sd 3:0:0:1: [sdd] Attached SCSI disk sd 3:0:0:3: [sde] Attached SCSI disk ... sd 2:0:0:0: Attached scsi generic sg0 type 0 sd 3:0:0:0: Attached scsi generic sg1 type 0 sd 3:0:0:2: Attached scsi generic sg2 type 0 sd 3:0:0:1: Attached scsi generic sg3 type 0 sd 3:0:0:3: Attached scsi generic sg4 type 0 ...
So, my new volumes are: sdb sdc sdd sde.
CREATING THE PHISICAL VOLUMES
[root@centoshost ~]# ls /dev/sd* /dev/sda /dev/sda1 /dev/sda2 /dev/sdb /dev/sdc /dev/sdd /dev/sde [root@centoshost ~]# pvcreate /dev/sdb Physical volume "/dev/sdb" successfully created [root@centoshost ~]# pvcreate /dev/sdc Physical volume "/dev/sdc" successfully created [root@centoshost ~]# pvcreate /dev/sdd Physical volume "/dev/sdd" successfully created [root@centoshost ~]# pvcreate /dev/sde Physical volume "/dev/sde" successfully created [root@centoshost ~]#
CREATING THE VOLUME GROUP
[root@centoshost ~]# vgcreate mytestvg /dev/sdb /dev/sdc /dev/sdd /dev/sde
Volume group "mytestvg" successfully created
[root@centoshost ~]# vgdisplay -v mytestvg
Using volume group(s) on command line
Finding volume group "mytestvg"
--- Volume group ---
VG Name mytestvg
System ID
Format lvm2
Metadata Areas 4
Metadata Sequence No 1
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 0
Open LV 0
Max PV 0
Cur PV 4
Act PV 4
VG Size 39.98 GiB
PE Size 4.00 MiB
Total PE 10236
Alloc PE / Size 0 / 0
Free PE / Size 10236 / 39.98 GiB
VG UUID VuOgyc-w2NO-wZ7j-dDnn-Hy77-OOgN-rLjXOt
--- Physical volumes ---
PV Name /dev/sdb
PV UUID cwLnS8-bDiV-OoXC-p6Mt-QxqT-WDLr-JjgjNZ
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sdc
PV UUID ChG7YS-Lpfu-606z-E5Vq-hrux-qxxx-HYEupJ
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sdd
PV UUID KL8MMX-L6tl-hdIm-PLko-11Nh-xpPg-MwIqBT
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sde
PV UUID MoLGEY-7J3e-YIdI-GPP1-50n2-F57e-ofu6Hu
PV Status allocatable
Total PE / Free PE 2559 / 2559
[root@centoshost ~]#
CREATING THE LOGICAL VOLUME
[root@centoshost ~]# lvcreate -l 2559 -n mytestlv1 mytestvg
Logical volume "mytestlv1" created
[root@centoshost ~]#
[root@centoshost ~]# vgdisplay -v mytestvg
Using volume group(s) on command line
Finding volume group "mytestvg"
--- Volume group ---
VG Name mytestvg
System ID
Format lvm2
Metadata Areas 4
Metadata Sequence No 2
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 0
Max PV 0
Cur PV 4
Act PV 4
VG Size 39.98 GiB
PE Size 4.00 MiB
Total PE 10236
Alloc PE / Size 2559 / 10.00 GiB
Free PE / Size 7677 / 29.99 GiB
VG UUID VuOgyc-w2NO-wZ7j-dDnn-Hy77-OOgN-rLjXOt
--- Logical volume ---
LV Path /dev/mytestvg/mytestlv1
LV Name mytestlv1
VG Name mytestvg
LV UUID v5Btut-Kxod-g9Zm-KqtK-9HRr-pddL-7ziFOM
LV Write Access read/write
LV Creation host, time centoshost, 2013-07-06 16:14:58 +0200
LV Status available
# open 0
LV Size 10.00 GiB
Current LE 2559
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3
--- Physical volumes ---
PV Name /dev/sdb
PV UUID cwLnS8-bDiV-OoXC-p6Mt-QxqT-WDLr-JjgjNZ
PV Status allocatable
Total PE / Free PE 2559 / 0
PV Name /dev/sdc
PV UUID ChG7YS-Lpfu-606z-E5Vq-hrux-qxxx-HYEupJ
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sdd
PV UUID KL8MMX-L6tl-hdIm-PLko-11Nh-xpPg-MwIqBT
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sde
PV UUID MoLGEY-7J3e-YIdI-GPP1-50n2-F57e-ofu6Hu
PV Status allocatable
Total PE / Free PE 2559 / 2559
[root@centoshost ~]# lvdisplay /dev/mytestvg/mytestlv1
--- Logical volume ---
LV Path /dev/mytestvg/mytestlv1
LV Name mytestlv1
VG Name mytestvg
LV UUID v5Btut-Kxod-g9Zm-KqtK-9HRr-pddL-7ziFOM
LV Write Access read/write
LV Creation host, time centoshost, 2013-07-06 16:14:58 +0200
LV Status available
# open 0
LV Size 10.00 GiB
Current LE 2559
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3
[root@centoshost ~]#
CREATING THE FILESYSTEM ON THE LOGICAL VOLUME
[root@centoshost ~]# mke2fs /dev/mytestvg/mytestlv1
mke2fs 1.41.12 (17-May-2010)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
655360 inodes, 2620416 blocks
131020 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=2684354560
80 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632
Writing inode tables: done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 32 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
[root@centoshost ~]# tune2fs -l /dev/mytestvg/mytestlv1
tune2fs 1.41.12 (17-May-2010)
Filesystem volume name: <none>
Last mounted on: <not available>
Filesystem UUID: ab9beb1c-2ded-4ae1-a083-c2f482ed074f
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: ext_attr resize_inode dir_index filetype sparse_super large_file
Filesystem flags: signed_directory_hash
Default mount options: (none)
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Inode count: 655360
Block count: 2620416
Reserved block count: 131020
Free blocks: 2573521
Free inodes: 655349
First block: 0
Block size: 4096
Fragment size: 4096
Reserved GDT blocks: 639
Blocks per group: 32768
Fragments per group: 32768
Inodes per group: 8192
Inode blocks per group: 512
Filesystem created: Sat Jul 6 16:19:40 2013
Last mount time: n/a
Last write time: Sat Jul 6 16:19:40 2013
Mount count: 0
Maximum mount count: 32
Last checked: Sat Jul 6 16:19:40 2013
Check interval: 15552000 (6 months)
Next check after: Thu Jan 2 15:19:40 2014
Reserved blocks uid: 0 (user root)
Reserved blocks gid: 0 (group root)
First inode: 11
Inode size: 256
Required extra isize: 28
Desired extra isize: 28
Default directory hash: half_md4
Directory Hash Seed: 7a3b64a5-abf6-4070-93ba-7ed4775e1dc5
[root@centoshost ~]# mount /dev/mytestvg/mytestlv1 /mnt/
[root@centoshost ~]# mount | grep test
/dev/mapper/mytestvg-mytestlv1 on /mnt type ext2 (rw)
[root@centoshost ~]# ls /mnt
lost+found
[root@centoshost ~]# df -m /mnt
Filesystem 1M-blocks Used Available Use% Mounted on
/dev/mapper/mytestvg-mytestlv1
10076 23 9542 1% /mnt
[root@centoshost ~]#
CREATING SOME BOGUS CONTENT
[root@centoshost ~]# cd /mnt
[root@centoshost mnt]# for x in $(seq 0 9); do dd if=/dev/zero of=zero${x}.bin bs=1024 count=10240; done
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0253373 s, 414 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.026879 s, 390 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0264344 s, 397 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.025419 s, 413 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0263466 s, 398 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0195509 s, 536 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0192691 s, 544 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0110749 s, 947 MB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0104302 s, 1.0 GB/s
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.0116289 s, 902 MB/s
[root@centoshost mnt]# ls -l
total 112876
drwx------. 2 root root 16384 Jul 6 16:19 lost+found
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero0.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero1.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero2.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero3.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero4.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero5.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero6.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero7.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero8.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero9.bin
[root@centoshost mnt]# df -m .
Filesystem 1M-blocks Used Available Use% Mounted on
/dev/mapper/mytestvg-mytestlv1
10076 123 9441 2% /mnt
[root@centoshost mnt]#
REDUCING A VOLUME GROUP - REMOVING PHISICAL VOLUMES TO IT:
[root@centoshost mnt]# pvscan PV /dev/sdb VG mytestvg lvm2 [10.00 GiB / 0 free] PV /dev/sdc VG mytestvg lvm2 [10.00 GiB / 10.00 GiB free] PV /dev/sdd VG mytestvg lvm2 [10.00 GiB / 10.00 GiB free] PV /dev/sde VG mytestvg lvm2 [10.00 GiB / 10.00 GiB free] PV /dev/sda2 VG vg_centoshost lvm2 [126.51 GiB / 0 free] Total: 5 [166.49 GiB] / in use: 5 [166.49 GiB] / in no VG: 0 [0 ] [root@centoshost mnt]# vgreduce mytestvg /dev/sde Removed "/dev/sde" from volume group "mytestvg" [root@centoshost mnt]# vgreduce mytestvg /dev/sdd /dev/sdc Removed "/dev/sdd" from volume group "mytestvg" Removed "/dev/sdc" from volume group "mytestvg" [root@centoshost mnt]# pvscan PV /dev/sdb VG mytestvg lvm2 [10.00 GiB / 0 free] PV /dev/sda2 VG vg_centoshost lvm2 [126.51 GiB / 0 free] PV /dev/sdc lvm2 [10.00 GiB] PV /dev/sdd lvm2 [10.00 GiB] PV /dev/sde lvm2 [10.00 GiB] Total: 5 [166.50 GiB] / in use: 2 [136.50 GiB] / in no VG: 3 [30.00 GiB] [root@centoshost mnt]#
EXTENDING A VOLUME GROUP - ADDING PHISICAL VOLUMES TO IT
[root@centoshost mnt]# vgextend mytestvg /dev/sdc Volume group "mytestvg" successfully extended [root@centoshost mnt]#
EXTENDING A LOGICAL VOLUME
[root@centoshost mnt]# lvextend -l +2559 /dev/mytestvg/mytestlv1
Extending logical volume mytestlv1 to 19.99 GiB
Logical volume mytestlv1 successfully resized
[root@centoshost mnt]# lvdisplay -v /dev/mytestvg/mytestlv1
Using logical volume(s) on command line
--- Logical volume ---
LV Path /dev/mytestvg/mytestlv1
LV Name mytestlv1
VG Name mytestvg
LV UUID v5Btut-Kxod-g9Zm-KqtK-9HRr-pddL-7ziFOM
LV Write Access read/write
LV Creation host, time centoshost, 2013-07-06 16:14:58 +0200
LV Status available
# open 1
LV Size 19.99 GiB
Current LE 5118
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3
[root@centoshost mnt]# pvscan
PV /dev/sdb VG mytestvg lvm2 [10.00 GiB / 0 free]
PV /dev/sdc VG mytestvg lvm2 [10.00 GiB / 0 free]
PV /dev/sda2 VG vg_centoshost lvm2 [126.51 GiB / 0 free]
PV /dev/sdd lvm2 [10.00 GiB]
PV /dev/sde lvm2 [10.00 GiB]
Total: 5 [166.50 GiB] / in use: 3 [146.50 GiB] / in no VG: 2 [20.00 GiB]
[root@centoshost mnt]# vgdisplay -v mytestvg
Using volume group(s) on command line
Finding volume group "mytestvg"
--- Volume group ---
VG Name mytestvg
System ID
Format lvm2
Metadata Areas 2
Metadata Sequence No 13
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 19.99 GiB
PE Size 4.00 MiB
Total PE 5118
Alloc PE / Size 5118 / 19.99 GiB
Free PE / Size 0 / 0
VG UUID VuOgyc-w2NO-wZ7j-dDnn-Hy77-OOgN-rLjXOt
--- Logical volume ---
LV Path /dev/mytestvg/mytestlv1
LV Name mytestlv1
VG Name mytestvg
LV UUID v5Btut-Kxod-g9Zm-KqtK-9HRr-pddL-7ziFOM
LV Write Access read/write
LV Creation host, time centoshost, 2013-07-06 16:14:58 +0200
LV Status available
# open 1
LV Size 19.99 GiB
Current LE 5118
Segments 2
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3
--- Physical volumes ---
PV Name /dev/sdb
PV UUID cwLnS8-bDiV-OoXC-p6Mt-QxqT-WDLr-JjgjNZ
PV Status allocatable
Total PE / Free PE 2559 / 0
PV Name /dev/sdc
PV UUID ChG7YS-Lpfu-606z-E5Vq-hrux-qxxx-HYEupJ
PV Status allocatable
Total PE / Free PE 2559 / 0
[root@centoshost mnt]#
EXTENDING A FILESYSTEM
[root@centoshost mnt]# resize2fs /dev/mytestvg/mytestlv1 $((4*5118))M # extent size * number of extents
resize2fs 1.41.12 (17-May-2010)
resize2fs: New size smaller than minimum (26802)
[root@centoshost mnt]# resize2fs /dev/mytestvg/mytestlv1 $((4*5118))M
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mytestvg/mytestlv1 is mounted on /mnt; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 2
resize2fs: Kernel does not support online resizing
[root@centoshost mnt]# cd
[root@centoshost ~]# umount /mnt/
[root@centoshost ~]# resize2fs /dev/mytestvg/mytestlv1 $((4*5118))M
resize2fs 1.41.12 (17-May-2010)
Please run 'e2fsck -f /dev/mytestvg/mytestlv1' first.
[root@centoshost ~]# e2fsck -f /dev/mytestvg/mytestlv1
e2fsck 1.41.12 (17-May-2010)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/mytestvg/mytestlv1: 21/655360 files (4.8% non-contiguous), 72536/2620416 blocks
[root@centoshost ~]# resize2fs /dev/mytestvg/mytestlv1 $((4*5118))M
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mytestvg/mytestlv1 to 5240832 (4k) blocks.
The filesystem on /dev/mytestvg/mytestlv1 is now 5240832 blocks long.
[root@centoshost ~]# mount /dev/mytestvg/mytestlv1 /mnt
[root@centoshost ~]# df -m /mnt
Filesystem 1M-blocks Used Available Use% Mounted on
/dev/mapper/mytestvg-mytestlv1
20151 128 19000 1% /mnt
[root@centoshost ~]# ls -l /mnt
total 102616
drwx------. 2 root root 16384 Jul 6 16:19 lost+found
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero0.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero1.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero2.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero3.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero4.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero5.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero6.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero7.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero8.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero9.bin
[root@centoshost ~]#
RISKY STUFF!!! - REDUCING THE FILESYSTEM AND THE LOGICAL VOLUME
[root@centoshost ~]# umount /mnt
[root@centoshost ~]# resize2fs /dev/mytestvg/mytestlv1 $((4*2559))M
resize2fs 1.41.12 (17-May-2010)
Please run 'e2fsck -f /dev/mytestvg/mytestlv1' first.
[root@centoshost ~]# e2fsck -f /dev/mytestvg/mytestlv1
e2fsck 1.41.12 (17-May-2010)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/mytestvg/mytestlv1: 21/1310720 files (4.8% non-contiguous), 114938/5240832 blocks
[root@centoshost ~]# resize2fs /dev/mytestvg/mytestlv1 $((4*2559))M
resize2fs 1.41.12 (17-May-2010)
Resizing the filesystem on /dev/mytestvg/mytestlv1 to 2620416 (4k) blocks.
The filesystem on /dev/mytestvg/mytestlv1 is now 2620416 blocks long.
[root@centoshost ~]# lvreduce -l -2559 /dev/mytestvg/mytestlv1
WARNING: Reducing active logical volume to 10.00 GiB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce mytestlv1? [y/n]: y
Reducing logical volume mytestlv1 to 10.00 GiB
Logical volume mytestlv1 successfully resized
[root@centoshost ~]# pvscan
PV /dev/sdb VG mytestvg lvm2 [10.00 GiB / 0 free]
PV /dev/sdc VG mytestvg lvm2 [10.00 GiB / 10.00 GiB free]
PV /dev/sda2 VG vg_centoshost lvm2 [126.51 GiB / 0 free]
PV /dev/sdd lvm2 [10.00 GiB]
PV /dev/sde lvm2 [10.00 GiB]
Total: 5 [166.50 GiB] / in use: 3 [146.50 GiB] / in no VG: 2 [20.00 GiB]
[root@centoshost ~]# mount /dev/mytestvg/mytestlv1 /mnt
[root@centoshost ~]# df -m /mnt
Filesystem 1M-blocks Used Available Use% Mounted on
/dev/mapper/mytestvg-mytestlv1
10076 123 9441 2% /mnt
[root@centoshost ~]# ls -l /mnt
total 102616
drwx------. 2 root root 16384 Jul 6 16:19 lost+found
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero0.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero1.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero2.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero3.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero4.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero5.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero6.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero7.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero8.bin
-rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero9.bin
[root@centoshost ~]# (cd /mnt; for x in $(seq 9); do cmp --verbose zero0.bin zero${x}.bin && echo "lucky... $x == 0"; done)
lucky... 1 == 0
lucky... 2 == 0
lucky... 3 == 0
lucky... 4 == 0
lucky... 5 == 0
lucky... 6 == 0
lucky... 7 == 0
lucky... 8 == 0
lucky... 9 == 0
[root@centoshost ~]#
CONVERTING A LOGICAL VOLUME - ADDING ONE MIRROR
[root@centoshost ~]# vgdisplay mytestvg -v
Using volume group(s) on command line
Finding volume group "mytestvg"
--- Volume group ---
VG Name mytestvg
System ID
Format lvm2
Metadata Areas 4
Metadata Sequence No 32
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 4
Act PV 4
VG Size 39.98 GiB
PE Size 4.00 MiB
Total PE 10236
Alloc PE / Size 2559 / 10.00 GiB
Free PE / Size 7677 / 29.99 GiB
VG UUID VuOgyc-w2NO-wZ7j-dDnn-Hy77-OOgN-rLjXOt
--- Logical volume ---
LV Path /dev/mytestvg/mytestlv1
LV Name mytestlv1
VG Name mytestvg
LV UUID v5Btut-Kxod-g9Zm-KqtK-9HRr-pddL-7ziFOM
LV Write Access read/write
LV Creation host, time centoshost, 2013-07-06 16:14:58 +0200
LV Status available
# open 1
LV Size 10.00 GiB
Current LE 2559
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3
--- Physical volumes ---
PV Name /dev/sdb
PV UUID cwLnS8-bDiV-OoXC-p6Mt-QxqT-WDLr-JjgjNZ
PV Status allocatable
Total PE / Free PE 2559 / 0
PV Name /dev/sdc
PV UUID ChG7YS-Lpfu-606z-E5Vq-hrux-qxxx-HYEupJ
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sdd
PV UUID KL8MMX-L6tl-hdIm-PLko-11Nh-xpPg-MwIqBT
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sde
PV UUID MoLGEY-7J3e-YIdI-GPP1-50n2-F57e-ofu6Hu
PV Status allocatable
Total PE / Free PE 2559 / 2559
[root@centoshost ~]# lvconvert -m1 /dev/mytestvg/mytestlv1
mytestvg/mytestlv1: Converted: 0.0%
...
mytestvg/mytestlv1: Converted: 100.0%
[root@centoshost ~]# vgdisplay mytestvg -v
Using volume group(s) on command line
Finding volume group "mytestvg"
--- Volume group ---
VG Name mytestvg
System ID
Format lvm2
Metadata Areas 4
Metadata Sequence No 34
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 1
Open LV 1
Max PV 0
Cur PV 4
Act PV 4
VG Size 39.98 GiB
PE Size 4.00 MiB
Total PE 10236
Alloc PE / Size 5119 / 20.00 GiB
Free PE / Size 5117 / 19.99 GiB
VG UUID VuOgyc-w2NO-wZ7j-dDnn-Hy77-OOgN-rLjXOt
--- Logical volume ---
LV Path /dev/mytestvg/mytestlv1
LV Name mytestlv1
VG Name mytestvg
LV UUID v5Btut-Kxod-g9Zm-KqtK-9HRr-pddL-7ziFOM
LV Write Access read/write
LV Creation host, time centoshost, 2013-07-06 16:14:58 +0200
LV Status available
# open 1
LV Size 10.00 GiB
Current LE 2559
Mirrored volumes 2
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3
--- Physical volumes ---
PV Name /dev/sdb
PV UUID cwLnS8-bDiV-OoXC-p6Mt-QxqT-WDLr-JjgjNZ
PV Status allocatable
Total PE / Free PE 2559 / 0
PV Name /dev/sdc
PV UUID ChG7YS-Lpfu-606z-E5Vq-hrux-qxxx-HYEupJ
PV Status allocatable
Total PE / Free PE 2559 / 0
PV Name /dev/sdd
PV UUID KL8MMX-L6tl-hdIm-PLko-11Nh-xpPg-MwIqBT
PV Status allocatable
Total PE / Free PE 2559 / 2559
PV Name /dev/sde
PV UUID MoLGEY-7J3e-YIdI-GPP1-50n2-F57e-ofu6Hu
PV Status allocatable
Total PE / Free PE 2559 / 2558
[root@centoshost ~]# pvscan
PV /dev/sdb VG mytestvg lvm2 [10.00 GiB / 0 free]
PV /dev/sdc VG mytestvg lvm2 [10.00 GiB / 0 free]
PV /dev/sdd VG mytestvg lvm2 [10.00 GiB / 10.00 GiB free]
PV /dev/sde VG mytestvg lvm2 [10.00 GiB / 9.99 GiB free]
PV /dev/sda2 VG vg_centoshost lvm2 [126.51 GiB / 0 free]
Total: 5 [166.49 GiB] / in use: 5 [166.49 GiB] / in no VG: 0 [0 ]
[root@centoshost ~]# df -m
Filesystem 1M-blocks Used Available Use% Mounted on
...
/dev/mapper/mytestvg-mytestlv1
10076 123 9441 2% /mnt
[root@centoshost ~]#
DOING A SNAPSHOT BACKUP OF A LOGICAL VOLUME
[root@centoshost ~]# lvcreate -l 2559 -s /dev/mapper/mytestvg-mytestlv1 -n mytestlv1-snap /dev/sdd WARNING: Snapshots of mirrors can deadlock under rare device failures. WARNING: Consider using the raid1 mirror type to avoid this. WARNING: See global/mirror_segtype_default in lvm.conf. Logical volume "mytestlv1-snap" created [root@centoshost ~]# lvscan ACTIVE Original '/dev/mytestvg/mytestlv1' [10.00 GiB] inherit ACTIVE Snapshot '/dev/mytestvg/mytestlv1-snap' [10.00 GiB] inherit ACTIVE '/dev/vg_centoshost/lv_root' [50.00 GiB] inherit ACTIVE '/dev/vg_centoshost/lv_home' [72.60 GiB] inherit ACTIVE '/dev/vg_centoshost/lv_swap' [3.91 GiB] inherit [root@centoshost ~]# mkdir /mnt2 [root@centoshost ~]# mount /dev/mytestvg/mytestlv1-snap /mnt2 [root@centoshost ~]# ls -l /mnt2 total 102616 drwx------. 2 root root 16384 Jul 6 16:19 lost+found -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero0.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero1.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero2.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero3.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero4.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero5.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero6.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero7.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero8.bin -rw-r--r--. 1 root root 10485760 Jul 6 16:48 zero9.bin [root@centoshost ~]#Then you may eventually backup the files to tape using you preferred software (tar for example) and remove the snapshot.
[root@centoshost ~]# pvscan PV /dev/sdb VG mytestvg lvm2 [10.00 GiB / 0 free] PV /dev/sdc VG mytestvg lvm2 [10.00 GiB / 0 free] PV /dev/sdd VG mytestvg lvm2 [10.00 GiB / 0 free] PV /dev/sde VG mytestvg lvm2 [10.00 GiB / 9.99 GiB free] PV /dev/sda2 VG vg_centoshost lvm2 [126.51 GiB / 0 free] Total: 5 [166.49 GiB] / in use: 5 [166.49 GiB] / in no VG: 0 [0 ] [root@centoshost ~]# umount /mnt2 [root@centoshost ~]# lvremove /dev/mytestvg/mytestlv1-snap Do you really want to remove active logical volume mytestlv1-snap? [y/n]: y Logical volume "mytestlv1-snap" successfully removed [root@centoshost ~]# pvscan PV /dev/sdb VG mytestvg lvm2 [10.00 GiB / 0 free] PV /dev/sdc VG mytestvg lvm2 [10.00 GiB / 0 free] PV /dev/sdd VG mytestvg lvm2 [10.00 GiB / 10.00 GiB free] PV /dev/sde VG mytestvg lvm2 [10.00 GiB / 9.99 GiB free] PV /dev/sda2 VG vg_centoshost lvm2 [126.51 GiB / 0 free] Total: 5 [166.49 GiB] / in use: 5 [166.49 GiB] / in no VG: 0 [0 ] [root@centoshost ~]#
RELATED COMMANDS, MANUALS AND OTHER FILES
[root@centoshost ~]# rpm -qd lvm2 /usr/share/doc/lvm2-2.02.98/COPYING /usr/share/doc/lvm2-2.02.98/COPYING.LIB /usr/share/doc/lvm2-2.02.98/INSTALL /usr/share/doc/lvm2-2.02.98/README /usr/share/doc/lvm2-2.02.98/VERSION /usr/share/doc/lvm2-2.02.98/WHATS_NEW /usr/share/man/man5/lvm.conf.5.gz /usr/share/man/man8/blkdeactivate.8.gz /usr/share/man/man8/fsadm.8.gz /usr/share/man/man8/lvchange.8.gz /usr/share/man/man8/lvconvert.8.gz /usr/share/man/man8/lvcreate.8.gz /usr/share/man/man8/lvdisplay.8.gz /usr/share/man/man8/lvextend.8.gz /usr/share/man/man8/lvm.8.gz /usr/share/man/man8/lvmchange.8.gz /usr/share/man/man8/lvmconf.8.gz /usr/share/man/man8/lvmdiskscan.8.gz /usr/share/man/man8/lvmdump.8.gz /usr/share/man/man8/lvmetad.8.gz /usr/share/man/man8/lvmsadc.8.gz /usr/share/man/man8/lvmsar.8.gz /usr/share/man/man8/lvreduce.8.gz /usr/share/man/man8/lvremove.8.gz /usr/share/man/man8/lvrename.8.gz /usr/share/man/man8/lvresize.8.gz /usr/share/man/man8/lvs.8.gz /usr/share/man/man8/lvscan.8.gz /usr/share/man/man8/pvchange.8.gz /usr/share/man/man8/pvck.8.gz /usr/share/man/man8/pvcreate.8.gz /usr/share/man/man8/pvdisplay.8.gz /usr/share/man/man8/pvmove.8.gz /usr/share/man/man8/pvremove.8.gz /usr/share/man/man8/pvresize.8.gz /usr/share/man/man8/pvs.8.gz /usr/share/man/man8/pvscan.8.gz /usr/share/man/man8/vgcfgbackup.8.gz /usr/share/man/man8/vgcfgrestore.8.gz /usr/share/man/man8/vgchange.8.gz /usr/share/man/man8/vgck.8.gz /usr/share/man/man8/vgconvert.8.gz /usr/share/man/man8/vgcreate.8.gz /usr/share/man/man8/vgdisplay.8.gz /usr/share/man/man8/vgexport.8.gz /usr/share/man/man8/vgextend.8.gz /usr/share/man/man8/vgimport.8.gz /usr/share/man/man8/vgimportclone.8.gz /usr/share/man/man8/vgmerge.8.gz /usr/share/man/man8/vgmknodes.8.gz /usr/share/man/man8/vgreduce.8.gz /usr/share/man/man8/vgremove.8.gz /usr/share/man/man8/vgrename.8.gz /usr/share/man/man8/vgs.8.gz /usr/share/man/man8/vgscan.8.gz /usr/share/man/man8/vgsplit.8.gz