Thursday, 30 January 2014


Many Occasion we used to get the task for extending the existing File systems when we don't have space in Volume Group. Let we can start from our High level plan. In the below example we are going to extend Fs LVOL1_mnt online on our unixrock test server.

High Level Plan

  • Identify the newly added disk.
  • Ensured the full backup of File system and required configurations backups.
  • Initialize and Add the disk into Volume group.
  • Extend the Logical Volume.
  • Resize the Logical Volume.

Currently FS size is
[root@unixrock /]# df -h /LVOL1_mnt
Filesystem              Size  Used Avail Use% Mounted on
/dev/mapper/vg01-LVOL1    24M  1.2M   22M    5% /LVOL1_mnt
[root@unixrock /]#

  Checking host SCSI connection before scanning the disk.
[root@unixrock /]# cat /proc/scsi/scsi
Attached devices:
Host: scsi1 Channel: 00 Id: 00 Lun: 00
  Vendor: NECVMWar Model: VMware IDE CDR10 Rev: 1.00
  Type:   CD-ROM                           ANSI  SCSI revision: 05
Host: scsi2 Channel: 00 Id: 00 Lun: 00
  Vendor: VMware,  Model: VMware Virtual S Rev: 1.0
  Type:   Direct-Access                    ANSI  SCSI revision: 02
Host: scsi5 Channel: 00 Id: 00 Lun: 00
  Vendor: OPNFILER Model: VIRTUAL-DISK     Rev: 0
  Type:   Direct-Access                    ANSI  SCSI revision: 04
Host: scsi5 Channel: 00 Id: 00 Lun: 01
  Vendor: OPNFILER Model: VIRTUAL-DISK     Rev: 0
  Type:   Direct-Access                    ANSI  SCSI revision: 04
Host: scsi5 Channel: 00 Id: 00 Lun: 02
  Vendor: OPNFILER Model: VIRTUAL-DISK     Rev: 0
  Type:   Direct-Access                    ANSI  SCSI revision: 04
Host: scsi5 Channel: 00 Id: 00 Lun: 03
  Vendor: OPNFILER Model: VIRTUAL-DISK     Rev: 0
  Type:   Direct-Access                    ANSI  SCSI revision: 04
[root@unixrock /]#
According to the above output, Scanning the new disk on host5 (Host: scsi5)
[root@unixrock ~]# echo "- - -" >/sys/class/scsi_host/host5/scan
[root@unixrock ~]#
[root@unixrock /]# fdisk -l

Disk /dev/sda: 21.5 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 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: 0x000d0e67

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          39      307200   83  Linux
Partition 1 does not end on cylinder boundary.
/dev/sda2              39         549     4096000   82  Linux swap / Solaris
Partition 2 does not end on cylinder boundary.
/dev/sda3             549        2611    16567296   83  Linux

Disk /dev/mapper/vg01-LVOL1: 25 MB, 25165824 bytes
255 heads, 63 sectors/track, 3 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/sdb: 234 MB, 234881024 bytes
8 heads, 56 sectors/track, 1024 cylinders
Units = cylinders of 448 * 512 = 229376 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8cb5a280

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1               1         100       22372   83  Linux

Disk /dev/sde: 234 MB, 234881024 bytes
8 heads, 56 sectors/track, 1024 cylinders
Units = cylinders of 448 * 512 = 229376 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x2d576e29

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1               1         100       22372   83  Linux

Disk /dev/sdf: 234 MB, 234881024 bytes
8 heads, 56 sectors/track, 1024 cylinders
Units = cylinders of 448 * 512 = 229376 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00000000
[root@unixrock /]#
Found the new disk /dev/sdf and initializing
[root@unixrock /]# pvcreate /dev/sdf
  Writing physical volume data to disk "/dev/sdf"
  Physical volume "/dev/sdf" successfully created
[root@unixrock /]#
[root@unixrock /]# pvs
  PV         VG   Fmt  Attr PSize   PFree
  /dev/sdd1  vg01 lvm2 a--   20.00m   8.00m
  /dev/sde1  vg01 lvm2 a--   20.00m   8.00m
  /dev/sdf        lvm2 a--  220.00m 220.00m
[root@unixrock /]#
Extending VolumeGroup with physical Volume
[root@unixrock /]# vgextend vg01 /dev/sdf
  Volume group "vg01" successfully extended
[root@unixrock /]#
[root@unixrock /]# pvs
  PV         VG   Fmt  Attr PSize   PFree
  /dev/sdd1  vg01 lvm2 a--   20.00m   8.00m
  /dev/sde1  vg01 lvm2 a--   20.00m   8.00m
  /dev/sdf   vg01 lvm2 a--  220.00m 220.00m
[root@unixrock /]#
Extending Logical Volume
[root@unixrock /]# lvextend -L +10M /dev/mapper/vg01-LVOL1
  Rounding size to boundary between physical extents: 12.00 MiB
  Extending logical volume LVOL1 to 36.00 MiB
  Logical volume LVOL1 successfully resized
[root@unixrock /]#
[root@unixrock /]# df -h /LVOL1_mnt
Filesystem              Size   Used  Avail Use% Mounted on
/dev/mapper/vg01-LVOL1    24M  1.2M   22M      5% /LVOL1_mnt
[root@unixrock /]#
Still its showing the same size even after extending the logical Volume.Creating File system on extending space
[root@unixrock /]# resize2fs /dev/mapper/vg01-LVOL1
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/mapper/vg01-LVOL1 is mounted on /LVOL1_mnt; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 1
Performing an on-line resize of /dev/mapper/vg01-LVOL1 to 36864 (1k) blocks.
The filesystem on /dev/mapper/vg01-LVOL1 is now 36864 blocks long.
[root@unixrock /]#
[root@unixrock /]# df -h /LVOL1_mnt
Filesystem              Size  Used Avail Use% Mounted on
/dev/mapper/vg01-LVOL1 36M  1.2M   33M   4% /LVOL1_mnt
[root@unixrock /]#
Yes..We have successfully Extended the existing Filesystem by online.

Thanks for reading this post, Please leave your valuable queries and comments, I will get back to you at earliest.