Jul 06 2012

Resizing the filesystem using Logical Volume Manager within Oracle Linux

Category: Linux,OSittichai @ 8:53 pm

Oftentimes we all run into the situation where the file system is full (or almost full) and need more space. This expansion task seems to be a lot easier when using the Logical Volume Manager (LVM) in Oracle Linux.

  • Review the current size.
[root@ol6 ~]# df -H
Filesystem                 Size   Used  Avail Use% Mounted on
/dev/mapper/vg_ol6-lv_root 27G    22G   3.8G  86% /
tmpfs                      1.3G   209M   1.1G  17% /dev/shm
/dev/sda1                  508M    97M   385M  21% /boot
Downloads                  750G   172G   578G  23% /media/sf_Downloads

Plan to add 30G to the root file system.

  • Create a partition on the newly-added disk.
[root@ol6 ~]# fdisk /dev/sdf
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel with disk identifier 0x0c04311f.
Changes will remain in memory only, until you decide to write them.

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 (1-3916, default 1): 
Using default value 1
Last cylinder, +cylinders or +size{K,M,G} (1-3916, default 3916): 
Using default value 3916

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
  •  Create a physical volume on top of it.
[root@ol6 ~]# pvcreate /dev/sdf1
  Writing physical volume data to disk "/dev/sdf1"
  Physical volume "/dev/sdf1" successfully created
  • Review the current volume. Note that currently there is no free extends (noted by zero value of the “Free PE / Size”).
[root@ol6 ~]# vgdisplay
  --- Volume group ---
  VG Name               vg_ol6
  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               29.51 GiB
  PE Size               4.00 MiB
  Total PE              7554
  Alloc PE / Size       7554 / 29.51 GiB
 Free PE / Size 0 / 0  
  VG UUID               2e2VHd-Mb3D-Uz0G-4Yec-tbfe-f3cI-7cvpby
  • Extend this volume with a new disk.
[root@ol6 ~]# vgextend vg_ol6 /dev/sdf1
  Volume group "vg_ol6" successfully extended
  • Check the volume again. The “Free PE / Size” is now 30G.
[root@ol6 ~]# vgdisplay
--- Volume group ---
VG Name vg_ol6
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 59.50 GiB
PE Size 4.00 MiB
Total PE 15233
Alloc PE / Size 7554 / 29.51 GiB
Free PE / Size 7679 / 30.00 GiB
VG UUID 2e2VHd-Mb3D-Uz0G-4Yec-tbfe-f3cI-7cvpby
  • Now let’s review the logical volume.
[root@ol6 ~]# lvdisplay
  --- Logical volume ---
  LV Path                /dev/vg_ol6/lv_root
  LV Name                lv_root
  VG Name                vg_ol6
  LV UUID                rd2d4X-vqE8-xENi-clCz-Oa0T-0R6X-RFCBDq
  LV Write Access        read/write
  LV Creation host, time , 
  LV Status              available
  # open                 1
 LV Size 25.10 GiB
  Current LE             6426
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

  --- Logical volume ---
  LV Path                /dev/vg_ol6/lv_swap
  LV Name                lv_swap
  VG Name                vg_ol6
  LV UUID                xM3Blz-wvpG-IUfF-WhWc-EHoI-I0xG-oeV1IR
  LV Write Access        read/write
  LV Creation host, time , 
  LV Status              available
  # open                 1
  LV Size                4.41 GiB
  Current LE             1128
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1

We want to add additional 30G into the existing /dev/vg_ol6/lv_root. So the total size will be 55.1GB.

  • We can extend the logical volume to the needed size.
[root@ol6 ~]# lvextend -L 55.10G /dev/vg_ol6/lv_root
  Rounding size to boundary between physical extents: 55.10 GiB
  Extending logical volume lv_root to 55.10 GiB
  Insufficient free space: 5120 extents needed, but only 5119 available

You may have to adjust the size if the initial specified size is too large.

[root@ol6 ~]# lvextend -L 55G /dev/vg_ol6/lv_root
  Extending logical volume lv_root to 55.00 GiB
  Logical volume lv_root successfully resized
  • Now finally you can extend the file system.
[root@ol6 ~]# resize2fs /dev/vg_ol6/lv_root 55G
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/vg_ol6/lv_root is mounted on /; on-line resizing required
old desc_blocks = 3, new_desc_blocks = 4
Performing an on-line resize of /dev/vg_ol6/lv_root to 14417920 (4k) blocks.
The filesystem on /dev/vg_ol6/lv_root is now 14417920 blocks long.
  • The file system is resized while the system is still on-line.
[root@ol6 ~]# df -H
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg_ol6-lv_root
55G 22G 33G 39% /
tmpfs 1.3G 209M 1.1G 17% /dev/shm
/dev/sda1 508M 97M 385M 21% /boot
Downloads 750G 172G 578G 23% /media/sf_Downloads

References:

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4 Responses to “Resizing the filesystem using Logical Volume Manager within Oracle Linux”

  1. Angel says:

    Great tutorial! Thank you!

  2. Angel says:

    Is there any sort of graphics UI for doing this?

  3. Jerad says:

    Thank you! Your tutorial was very helpful. I needed more space on the VM I use to practice working with Oracle DB.

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