This post will covers the steps to create additional Logical volume manager (LVM) on CentOS 6.3. This will very useful when the production system facing run out of disk space to store data. Sometimes there is another request for them to create additional LVM for new system or to store data. It is possible to perform this task if that system administrator has the right skill on linux. Otherwise, they will put themselves and the organization in the disaster or risk as working with the system’s data is on of the most critical job that must be perform with the right steps and skills. Follow below steps :
1. Assumed that second disk has been added called /dev/sdb. Create new partition for /dev/sdb using below command :
[root@centos63 ~]# fdisk /dev/sdb
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0xd29f2d59.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
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').
Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-652, default 1):
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-652, default 652):
Using default value 652
Command (m for help): p
Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 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: 0xd29f2d59
Device Boot Start End Blocks Id System
/dev/sdb1 1 652 5237158+ 83 Linux
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)
Command (m for help): p
Disk /dev/sdb: 5368 MB, 5368709120 bytes
255 heads, 63 sectors/track, 652 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: 0xd29f2d59
Device Boot Start End Blocks Id System
/dev/sdb1 1 652 5237158+ 8e Linux LVM
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
Syncing disks.
2. Convert this disk into a physical volume :
[root@centos63 ~]# pvcreate /dev/sdb1 Writing physical volume data to disk "/dev/sdb1" Physical volume "/dev/sdb1" successfully created
Display the physical volume :
[root@centos63 ~]# pvdisplay --- Physical volume --- PV Name /dev/sda2 VG Name vg_centos63 PV Size 7.51 GiB / not usable 3.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 1922 Free PE 0 Allocated PE 1922 PV UUID 521faS-HW2C-nUrs-yI1E-4OO9-eLmj-1e3bGW "/dev/sdb1" is a new physical volume of "4.99 GiB" --- NEW Physical volume --- PV Name /dev/sdb1 VG Name PV Size 4.99 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID qTmTeq-8qoL-xxEk-Dj5V-zOjl-vEag-P6Jl7L
3. With the physical volume created we now need to create new volume group for it. In this case i will give the volume group name vg_data.
[root@centos63 ~]# vgcreate vg_data /dev/sdb1 Volume group "vg_data" successfully created
Display the volume group :
[root@centos63 ~]# vgdisplay --- Volume group --- VG Name vg_data System ID Format lvm2 Metadata Areas 1 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 1 Act PV 1 VG Size 4.99 GiB PE Size 4.00 MiB Total PE 1278 Alloc PE / Size 0 / 0 Free PE / Size 1278 / 4.99 GiB VG UUID YV3IYN-3CF9-3Yd1-69ue-wcq4-0UKk-Zk49Vk --- Volume group --- VG Name vg_centos63 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 7.51 GiB PE Size 4.00 MiB Total PE 1922 Alloc PE / Size 1922 / 7.51 GiB Free PE / Size 0 / 0 VG UUID G3H7s2-0yfo-vU9W-5g9g-fq9K-tpNO-U2Y7BQ
4. Create logical volumes with the name of centos63_vol into vg_data volume group :
[root@centos63 ~]# lvcreate --name centos63_vol -l 100%FREE vg_data Logical volume "centos63_vol" created
Display logical volume :
[root@centos63 ~]# lvdisplay --- Logical volume --- LV Path /dev/vg_data/centos63_vol LV Name centos63_vol VG Name vg_data LV UUID bVRJwM-5CuR-mLf4-tqHV-j5e4-cs3o-ffKL41 LV Write Access read/write LV Creation host, time centos63.ehowstuff.local, 2012-09-28 22:55:13 +0800 LV Status available # open 0 LV Size 4.99 GiB Current LE 1278 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:2 --- Logical volume --- LV Path /dev/vg_centos63/lv_root LV Name lv_root VG Name vg_centos63 LV UUID 3Se9Zl-RmAu-f707-1Fv2-wMvX-oH3z-maExU0 LV Write Access read/write LV Creation host, time centos63.ehowstuff.local, 2012-07-15 20:17:31 +0800 LV Status available # open 1 LV Size 5.54 GiB Current LE 1418 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 --- Logical volume --- LV Path /dev/vg_centos63/lv_swap LV Name lv_swap VG Name vg_centos63 LV UUID KijzOf-uPjy-JbJd-dcjw-u0XO-aqPA-2GKScq LV Write Access read/write LV Creation host, time centos63.ehowstuff.local, 2012-07-15 20:17:33 +0800 LV Status available # open 1 LV Size 1.97 GiB Current LE 504 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:1
5. Format the LVM using mke2fs with -j switch command :
[root@centos63 ~]# mke2fs -j /dev/vg_data/centos63_vol
[root@centos63 ~]# mke2fs -j /dev/vg_data/centos63_vol
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
327680 inodes, 1308672 blocks
65433 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=1342177280
40 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
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 37 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.
6. Create a mount point for the newly created logical volume :
[root@centos63 ~]# mkdir /mydata
7. Define mount point to use this partitions :
[root@centos63 ~]# e2label /dev/vg_data/centos63_vol /mydata
8. Modify /etc/fstab and add the following:
[root@centos63 ~]# vi /etc/fstab
/dev/vg_data/centos63_vol /mydata ext4 defaults 1 1
# # /etc/fstab # Created by anaconda on Sun Jul 15 20:17:38 2012 # # Accessible filesystems, by reference, are maintained under '/dev/disk' # See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info # /dev/mapper/vg_centos63-lv_root / ext4 defaults 1 1 UUID=2217c7b1-4467-4c81-8596-c3ee7758e2cc /boot ext4 defaults 1 2 /dev/mapper/vg_centos63-lv_swap swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 /dev/vg_data/centos63_vol /mydata ext4 defaults 1 1
9. Mount the newly created logical volume :
[root@centos63 ~]# mount /mydata
10. The newly created logical volume will now mount automatically each time the system is booted.
[root@centos63 ~]# df -lh
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_centos63-lv_root
5.5G 2.0G 3.3G 39% /
tmpfs 504M 0 504M 0% /dev/shm
/dev/sda1 485M 65M 395M 15% /boot
/dev/mapper/vg_data-centos63_vol
5.0G 139M 4.6G 3% /mydata
