Tuesday, March 23, 2010

REDHAT LVM determine free disk space and move LVM aroun

Determine free space

# pvscan
pvscan -- reading all physical volumes (this may take a while...)
pvscan -- ACTIVE PV "/dev/sda" of VG "dev" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sdb" of VG "sales" [1.95 GB / 1.27 GB free]
pvscan -- ACTIVE PV "/dev/sdc" of VG "ops" [1.95 GB / 564 MB free]
pvscan -- ACTIVE PV "/dev/sdd" of VG "dev" [1.95 GB / 0 free]
pvscan -- ACTIVE PV "/dev/sde" of VG "ops" [1.95 GB / 1.9 GB free]
pvscan -- ACTIVE PV "/dev/sdf" of VG "dev" [1.95 GB / 1.33 GB free]
pvscan -- ACTIVE PV "/dev/sdg1" of VG "ops" [996 MB / 432 MB free]
pvscan -- ACTIVE PV "/dev/sdg2" of VG "dev" [996 MB / 632 MB free]
pvscan -- total: 8 [13.67 GB] / in use: 8 [13.67 GB] / in no VG: 0 [0]


We decide to reallocate /dev/sdg1 and /dev/sdg2 to design so first we have to move the physical extents into the free areas of the other volumes (in this case /dev/sdf for volume group dev and /dev/sde for volume group ops).

Move data off the disks to be used

Some space is still used on the chosen volumes so it is necessary to move that used space off onto some others.

Move all the used physical extents from /dev/sdg1 to /dev/sde and from /dev/sdg2 to /dev/sdf

# pvmove /dev/sdg1 /dev/sde
pvmove -- moving physical extents in active volume group "ops"
pvmove -- WARNING: moving of active logical volumes may cause data loss!
pvmove -- do you want to continue? [y/n] y
pvmove -- doing automatic backup of volume group "ops"
pvmove -- 141 extents of physical volume "/dev/sdg1" successfully moved

# pvmove /dev/sdg2 /dev/sdf
pvmove -- moving physical extents in active volume group "dev"
pvmove -- WARNING: moving of active logical volumes may cause data loss!
pvmove -- do you want to continue? [y/n] y
pvmove -- doing automatic backup of volume group "dev"
pvmove -- 91 extents of physical volume "/dev/sdg2" successfully moved

Make a file system on the volume ext3

# mkfs.ext3 /dev/datavg01/datalv01
mke2fs 1.35 (28-Feb-2004)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
19660800 inodes, 39305216 blocks
1965260 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
1200 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872

Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 39 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.



Mount the new volume

# mkdir -p /mnt/design/users
# mount /dev/datavg01/datalv01 /mnt/design/users/


It's also a good idea to add an entry for this file system in your /etc/fstab file as follows:

/dev/datavg01/datalv01 /mnt/design/users ext3 defaults 1 2