RHEL6-17-LOGICAL VOLUME MANAGER (LVM)-4

RHEL6-17-LOGICAL VOLUME MANAGER (LVM)-4

LVM OPERATIONS:

How to resize the logical volume with “lvresize”…?

How to rename the volume group (vgrename)…?

How to rename the logical volume (lvrename)…?

How to make the changes effective after vgrename and lvrename…?

[root@rhel6-client1 ~]# pvcreate /dev/sdb4

  Physical volume "/dev/sdb4" successfully created

[root@rhel6-client1 ~]# vgextend vg01 /dev/sdb4

  Volume group "vg01" successfully extended

[root@rhel6-client1 ~]# lvextend --size +500M /dev/vg01/mylv

  Extending logical volume mylv to 2.09 GiB

  Logical volume mylv successfully resized

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

  mylv01        myvg01 -wi-a---- 200.00m                                       

  mylv          vg01   -wi-ao---   2.09g                                       

  mylv2         vg01   -wi-a----   3.39g

                                       

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

Filesystem            Size  Used Avail Use% Mounted on

/dev/sda6              15G  6.3G  7.4G  46% /

tmpfs                 937M   76K  937M   1% /dev/shm

/dev/sda1             485M   37M  423M   8% /boot

/dev/sda3            1008M   34M  924M   4% /home

/dev/sda2             2.9G   69M  2.7G   3% /opt

/dev/mapper/vg01-mylv

                      1.6G   35M  1.5G   3% /mylv ççç

[root@rhel6-client1 ~]#

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

resize2fs 1.41.12 (17-May-2010)

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

old desc_blocks = 1, new_desc_blocks = 1

Performing an on-line resize of /dev/vg01/mylv to 546816 (4k) blocks.

The filesystem on /dev/vg01/mylv is now 546816 blocks long.

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

Filesystem            Size  Used Avail Use% Mounted on

/dev/sda6              15G  6.3G  7.4G  46% /

tmpfs                 937M   76K  937M   1% /dev/shm

/dev/sda1             485M   37M  423M   8% /boot

/dev/sda3            1008M   34M  924M   4% /home

/dev/sda2             2.9G   69M  2.7G   3% /opt

/dev/mapper/vg01-mylv

                      2.1G   35M  2.0G   2% /mylv ççç

Good, The command “lvresize” is similar to “lvextend”.

Can I reduce size with “lvresize”…?

[root@rhel6-client1 ~]# lvextend --size -800M /dev/vg01/mylv

  Negative argument not permitted - use lvreduce

  Run `lvextend --help' for more information.

[root@rhel6-client1 ~]# lvextend --size 1G /dev/vg01/mylv

  New size given (256 extents) not larger than existing size (334 extents)

  Run `lvextend --help' for more information.

Means I cannot reduce size.

[root@rhel6-client1 ~]# lvreduce -L -800M /dev/vg01/mylv

  WARNING: Reducing active and open logical volume to 1.30 GiB

  THIS MAY DESTROY YOUR DATA (filesystem etc.)

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

  Reducing logical volume mylv to 1.30 GiB

  Logical volume mylv successfully resized

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

  mylv01        myvg01 -wi-a---- 200.00m                                       

  mylv          vg01   -wi-ao---   1.30g                                       

  mylv2         vg01   -wi-a----   3.39g 

[root@rhel6-client1 ~]# lvextend --size 1200M /dev/vg01/mylv

  New size given (300 extents) not larger than existing size (334 extents)

  Run `lvextend --help' for more information.

Why this error…?

This is why because I am again reducing the size.

Now I will try to resize with greater size than existing.

[root@rhel6-client1 ~]# lvextend --size 1500M /dev/vg01/mylv

  Extending logical volume mylv to 1.46 GiB

  Logical volume mylv successfully resized

Done.

Being super talented, I can reduce size with some arguments, but do it on your own risk.

[root@rhel6-client1 ~]# lvresize --resizefs --size -500M /dev/vg01/mylv

Do you want to unmount "/mylv"? [Y|n] y ç

fsck from util-linux-ng 2.17.2

/dev/mapper/vg01-mylv: The filesystem size (according to the superblock) is 546816 blocks

The physical size of the device is 384000 blocks

Either the superblock or the partition table is likely to be corrupt!

/dev/mapper/vg01-mylv: UNEXPECTED INCONSISTENCY; RUN fsck MANUALLY.

        (i.e., without -a or -p options)

resize2fs 1.41.12 (17-May-2010)

Please run 'e2fsck -f /dev/mapper/vg01-mylv' first.

fsadm: Resize ext4 failed

mount: wrong fs type, bad option, bad superblock on /dev/mapper/vg01-mylv,

       missing codepage or helper program, or other error

       In some cases useful info is found in syslog - try

       dmesg | tail  or so

  fsadm failed: 1

  Filesystem resize failed.

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

e2fsck 1.41.12 (17-May-2010)

The filesystem size (according to the superblock) is 546816 blocks

The physical size of the device is 384000 blocks

Either the superblock or the partition table is likely to be corrupt!

Abort<y>? yes

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

e2fsck 1.41.12 (17-May-2010)

The filesystem size (according to the superblock) is 546816 blocks

The physical size of the device is 384000 blocks

Either the superblock or the partition table is likely to be corrupt!

Abort? yes

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

resize2fs 1.41.12 (17-May-2010)

Please run 'e2fsck -f /dev/vg01/mylv' first.

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

e2fsck 1.41.12 (17-May-2010)

The filesystem size (according to the superblock) is 546816 blocks

The physical size of the device is 384000 blocks

Either the superblock or the partition table is likely to be corrupt!

Abort<y>? no

Pass 1: Checking inodes, blocks, and sizes

Error reading block 425986 (Invalid argument) while getting next inode from scan.  Ignore error<y>? yes

Force rewrite<y>? yes

Error writing block 425986 (Invalid argument) while getting next inode from scan.  Ignore error<y>? yes

Error reading block 425987 (Invalid argument) while getting next inode from scan.  Ignore error<y>? yes

Force rewrite<y>? yes

Error writing block 425987 (Invalid argument) while getting next inode from scan.  Ignore error<y>? yes

Error reading block 425988 (Invalid argument) while getting next inode from scan.  Ignore error<y>? yes

Force rewrite<y>? yes

Error writing block 425988 (Invalid argument) while getting next inode from scan.  Ignore error<y>? yes

Error reading block 425989 (Invalid argument) while getting next inode from scan.  Ignore error<y>? yes

Force rewrite<y>? yes

/dev/vg01/mylv: e2fsck canceled.

/dev/vg01/mylv: ********** WARNING: Filesystem still has errors **********

See, what happened!!! … now all data lost and we need to recreate FS.

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

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

96000 inodes, 384000 blocks

19200 blocks (5.00%) reserved for the super user

First data block=0

Maximum filesystem blocks=394264576

12 block groups

32768 blocks per group, 32768 fragments per group

8000 inodes per group

Superblock backups stored on blocks:

        32768, 98304, 163840, 229376, 294912

Writing inode tables: done

Creating journal (8192 blocks): done

Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 34 mounts or

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

[root@rhel6-client1 ~]# mount –a

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

Filesystem            Size  Used Avail Use% Mounted on

/dev/sda6              15G  6.3G  7.4G  46% /

tmpfs                 937M   76K  937M   1% /dev/shm

/dev/sda1             485M   37M  423M   8% /boot

/dev/sda3            1008M   34M  924M   4% /home

/dev/sda2             2.9G   69M  2.7G   3% /opt

/dev/mapper/vg01-mylv

                      1.5G   35M  1.4G   3% /mylv

[root@rhel6-client1 ~]#

LOGICAL VOLUME (LV) RENAME:

# lvrename VG_Name  Old_LV_name New_LV_name

[root@rhel6-client1 ~]# lvrename vg01 mylv mylvtest1

  Renamed "mylv" to "mylvtest1" in volume group "vg01"

LV is renamed but is it effective…?

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

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg01-mylv

                      1.5G   35M  1.4G   3% /mylv

No, then what should we do…?

Remount the FS,

[root@rhel6-client1 ~]# mount /dev/vg01/mylvtest1 /mylv

mount: /dev/mapper/vg01-mylvtest1 already mounted or /mylv busy

mount: according to mtab, /dev/mapper/vg01-mylv is already mounted on /mylv

[root@rhel6-client1 ~]# umount /mylv

[root@rhel6-client1 ~]# mount /dev/vg01/mylvtest1 /mylv

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

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg01-mylvtest1

                      1.5G   35M  1.4G   3% /mylv

Need to change the entry in “fstab” as well.

VOLUME GROUP (VG) RENAME:

# vgrename Old_VG_name New_VG_name

[root@rhel6-client1 ~]# vgrename vg01 vg-test01

  Volume group "vg01" successfully renamed to "vg-test01"

Is it effective…?

[root@rhel6-client1 ~]# vgs

  VG        #PV #LV #SN Attr   VSize VFree

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

  vg-test01   3   4   0 wz--n- 8.99g 1.45g

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

Technically Yes… but …… but …….

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

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg01-mylvtest1

                      1.5G   35M  1.4G   3% /mylv

[root@rhel6-client1 ~]# umount /mylv

[root@rhel6-client1 ~]# mount /dev/vg-test01/mylvtest1 /mylv

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

Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/vg--test01-mylvtest1

                      1.5G   35M  1.4G   3% /mylv

Need to change the entry in “fstab” as well.