RHEL6-16-LOGICAL VOLUME MANAGER (LVM)-3

RHEL6-16-LOGICAL VOLUME MANAGER (LVM)-3

LVM OPERATIONS:

How to extend/increase volume group space?

“vgextend”

How to extend/increase logical volume space?

“lvextend”

How to reduce/decrease logical volume space?

“lvreduce”

How to reduce/decrease volume group space?

“vgreduce”

[root@rhel6-client1 ~]# vgs

  VG     #PV #LV #SN Attr   VSize VFree

  myvg01   3   4   0 wz--n- 9.99g 9.20g

  vg01     2   4   0 wz--n- 7.99g    0 ççç No free space

  vg02     1   3   0 wz--n- 2.00g    0

I have 3 vg’s and I want to increase the size for “vg01”

Let’s check how many PV’s I have.

[root@rhel6-client1 ~]# pvs

  PV         VG     Fmt  Attr PSize PFree

  /dev/sdb1  vg01   lvm2 a--  5.00g    0

  /dev/sdb2  vg01   lvm2 a--  3.00g    0

  /dev/sdb3  vg02   lvm2 a--  2.00g    0

  /dev/sdc1  myvg01 lvm2 a--  5.00g 4.55g

  /dev/sdc2  myvg01 lvm2 a--  2.00g 1.75g

  /dev/sdc3  myvg01 lvm2 a--  3.00g 2.89g

There is no PV which I can add to “vg01”, I need another PV.

[root@rhel6-client1 ~]# fdisk -cu /dev/sdd

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel

Building a new DOS disklabel with disk identifier 0x84af01a1.

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)

Command (m for help): n

Command action

   e   extended

   p   primary partition (1-4)

p

Partition number (1-4): 1

First sector (2048-41943039, default 2048):

Using default value 2048

Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): +2G

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

[root@rhel6-client1 ~]# pvcreate /dev/sdd1

  Physical volume "/dev/sdd1" successfully created

[root@rhel6-client1 ~]# pvs

  PV         VG     Fmt  Attr PSize PFree

  /dev/sdb1  vg01   lvm2 a--  5.00g    0

  /dev/sdb2  vg01   lvm2 a--  3.00g    0

  /dev/sdb3  vg02   lvm2 a--  2.00g    0

  /dev/sdc1  myvg01 lvm2 a--  5.00g 4.55g

  /dev/sdc2  myvg01 lvm2 a--  2.00g 1.75g

  /dev/sdc3  myvg01 lvm2 a--  3.00g 2.89g

  /dev/sdd1         lvm2 a--  2.00g 2.00g ççç

EXTEND VOLUME GROUP:

[root@rhel6-client1 ~]# vgextend vg01 /dev/sdd1

  Volume group "vg01" successfully extended

[root@rhel6-client1 ~]# vgs

  VG     #PV #LV #SN Attr   VSize VFree

  myvg01   3   4   0 wz--n- 9.99g 9.20g

  vg01     3   4   0 wz--n- 9.99g 2.00g ççç 2gb added and free

  vg02     1   3   0 wz--n- 2.00g    0

Now I need to increase LV space under vg01.

[root@rhel6-client1 ~]# mkfs.ext4 /dev/vg01/lvol0

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

65536 inodes, 262144 blocks

13107 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=268435456

8 block groups

32768 blocks per group, 32768 fragments per group

8192 inodes per group

Superblock backups stored on blocks:

        32768, 98304, 163840, 229376

Writing inode tables: done

Creating journal (8192 blocks): done

Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 25 mounts or

180 days, whichever comes first.  Use tune2fs -c or -i to override.

[root@rhel6-client1 ~]# mkdir /lvol0

[root@rhel6-client1 ~]# mount /dev/vg01/lvol0 /lvol0

[root@rhel6-client1 ~]# df -kh /lvol0

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg01-lvol0

                     1008M   34M  924M   4% /lvol0

[root@rhel6-client1 ~]#

EXTEND LOGICAL VOLUME GROUP:

[root@rhel6-client1 ~]# lvextend -L +300M /dev/vg01/lvol0

  Extending logical volume lvol0 to 1.29 GiB

  Logical volume lvol0 successfully resized

Size is increased but it is not effective,

[root@rhel6-client1 ~]# lvs |grep lvol0

  lvol0         vg01   -wi-ao---   1.29g

[root@rhel6-client1 ~]# df -kh /lvol0

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg01-lvol0

                     1008M   34M  924M   4% /lvol0

RESIZING FILE SYSTEM:

[root@rhel6-client1 ~]# resize2fs /dev/vg01/lvol0

resize2fs 1.41.12 (17-May-2010)

Filesystem at /dev/vg01/lvol0 is mounted on /lvol0; on-line resizing required

old desc_blocks = 1, new_desc_blocks = 1

Performing an on-line resize of /dev/vg01/lvol0 to 338944 (4k) blocks.

The filesystem on /dev/vg01/lvol0 is now 338944 blocks long.

[root@rhel6-client1 ~]# df -kh /lvol0

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg01-lvol0

                      1.3G   34M  1.2G   3% /lvol0

Now I think, there was no need to increase the size of “lvol0”, so I want my space back.

Better to take the backup of contents before reducing, to avoid any mishap.

Unmount the FS

[root@rhel6-client1 ~]# fsck -y /dev/vg01/lvol0

fsck from util-linux-ng 2.17.2

e2fsck 1.41.12 (17-May-2010)

/dev/mapper/vg01-lvol0: clean, 11/90112 files, 14242/338944 blocks

[root@rhel6-client1 ~]# e2fsck -ff /dev/vg01/lvol0

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/vg01/lvol0: 11/90112 files (0.0% non-contiguous), 14242/338944 blocks 

[root@rhel6-client1 ~]# resize2fs /dev/vg01/lvol0 700M

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/vg01/lvol0 to 179200 (4k) blocks.

The filesystem on /dev/vg01/lvol0 is now 179200 blocks long.

[root@rhel6-client1 ~]# lvs |grep lvol0

  lvol0         vg01   -wi-a----   1.29g

REDUCING LOGICAL VOLUME GROUP:

[root@rhel6-client1 ~]# lvreduce -L -500M /dev/vg01/lvol0

  WARNING: Reducing active logical volume to 824.00 MiB

  THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce lvol0? [y/n]: y

  Reducing logical volume lvol0 to 824.00 MiB

  Logical volume lvol0 successfully resized

[root@rhel6-client1 ~]# lvs |grep lvol0

  lvol0         vg01   -wi-a---- 824.00m

[root@rhel6-client1 ~]#

I did wrong, I wanted to reduce it to 700MB. What I supposed to do is to cut 600MB from 1.29G to get 700MB.

[root@rhel6-client1 ~]# lvreduce -L -100M /dev/vg01/lvol0

  WARNING: Reducing active logical volume to 724.00 MiB

  THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce lvol0? [y/n]: y

  Reducing logical volume lvol0 to 724.00 MiB

  Logical volume lvol0 successfully resized

You have new mail in /var/spool/mail/root

[root@rhel6-client1 ~]# lvs |grep lvol0

  lvol0         vg01   -wi-a---- 724.00m

Or we can also go with PE size by –l,

[root@rhel6-client1 ~]# lvextend -L +600M /dev/vg01/lvol0

  Extending logical volume lvol0 to 1.29 GiB

  Logical volume lvol0 successfully resized

[root@rhel6-client1 ~]# resize2fs /dev/vg01/lvol0

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/vg01/lvol0 to 338944 (4k) blocks.

The filesystem on /dev/vg01/lvol0 is now 338944 blocks long.

[root@rhel6-client1 ~]# lvs |grep lvol0

  lvol0         vg01   -wi-a----   1.29g

Now we need to reduce the FS size to 700MB.

RESIZING FILE SYSTEM:

[root@rhel6-client1 ~]# resize2fs /dev/vg01/lvol0 700M

resize2fs 1.41.12 (17-May-2010)

Resizing the filesystem on /dev/vg01/lvol0 to 179200 (4k) blocks.

The filesystem on /dev/vg01/lvol0 is now 179200 blocks long.

[root@rhel6-client1 ~]# e2fsck /dev/vg01/lvol0

e2fsck 1.41.12 (17-May-2010)

/dev/vg01/lvol0: clean, 11/49152 files, 11542/179200 blocks

[root@rhel6-client1 ~]# vgdisplay /dev/vg01 |grep -i "pe size"

  PE Size               4.00 MiB

We want to make a FS of 700MB size.

[root@rhel6-client1 ~]# bc

bc 1.06.95

Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc.

This is free software with ABSOLUTELY NO WARRANTY.

For details type `warranty'.

1.29*1024

1320.96 => total size in MB

1320-600 => subtracting 600Mb to get 700MB of FS size

720 => got the size

600/4 => PE size is of 4MB, dividing 600MB with 4MB to get exact PE size

150 => this is the PE size we need to reduce from total

[root@rhel6-client1 ~]# lvreduce -l 150 /dev/vg01/lvol0

  WARNING: Reducing active logical volume to 600.00 MiB

  THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce lvol0? [y/n]: y

  Reducing logical volume lvol0 to 600.00 MiB

  Logical volume lvol0 successfully resized

[root@rhel6-client1 ~]# lvs |grep lvol0

  lvol0         vg01   -wi-a---- 600.00m

OOOPPPPsssssss…. Again did mistake. Instead of reducing I marked it for grand total 600MB.

I supposed to minus the PE size from total space. Let’s do it again.

[root@rhel6-client1 ~]# lvextend -L +700M /dev/vg01/lvol0

  Extending logical volume lvol0 to 1.27 GiB

  Logical volume lvol0 successfully resized

[root@rhel6-client1 ~]# lvreduce -l -150 /dev/vg01/lvol0

  WARNING: Reducing active logical volume to 700.00 MiB

  THIS MAY DESTROY YOUR DATA (filesystem etc.)

Do you really want to reduce lvol0? [y/n]: y

  Reducing logical volume lvol0 to 700.00 MiB

  Logical volume lvol0 successfully resized

[root@rhel6-client1 ~]# lvs |grep lvol0

  lvol0         vg01   -wi-a---- 700.00m

[root@rhel6-client1 ~]#

Now Good.

[root@rhel6-client1 ~]# resize2fs /dev/vg01/lvol0

resize2fs 1.41.12 (17-May-2010)

The filesystem is already 179200 blocks long.  Nothing to do!

We need to take care of “-“ or “no sign”.

-   Means reduce it from whatever it is now.

No sign means make it of whatever size I had given.

Now I want to reduce the volume group “vg01” and get my /dev/sdd1 back.

Let’s check the status first,

[root@rhel6-client1 ~]# pvs

  PV         VG     Fmt  Attr PSize PFree

  /dev/sdb1  vg01   lvm2 a--  5.00g 324.00m

  /dev/sdb2  vg01   lvm2 a--  3.00g      0

  /dev/sdb3  vg02   lvm2 a--  2.00g      0

  /dev/sdc1  myvg01 lvm2 a--  5.00g   4.55g

  /dev/sdc2  myvg01 lvm2 a--  2.00g   1.75g

  /dev/sdc3  myvg01 lvm2 a--  3.00g   2.89g

  /dev/sdd1  vg01   lvm2 a--  2.00g   2.00g ç its free

REDUCING VOLUME GROUP:

[root@rhel6-client1 ~]# vgreduce vg01 /dev/sdd1

  Removed "/dev/sdd1" from volume group "vg01"

[root@rhel6-client1 ~]# pvs

  PV         VG     Fmt  Attr PSize PFree

  /dev/sdb1  vg01   lvm2 a--  5.00g 324.00m

  /dev/sdb2  vg01   lvm2 a--  3.00g      0

  /dev/sdb3  vg02   lvm2 a--  2.00g      0

  /dev/sdc1  myvg01 lvm2 a--  5.00g   4.55g

  /dev/sdc2  myvg01 lvm2 a--  2.00g   1.75g

  /dev/sdc3  myvg01 lvm2 a--  3.00g   2.89g

  /dev/sdd1         lvm2 a--  2.00g   2.00g