LVM: Extend SWAP size by growing existing Logical Volume -

LVM: Extend SWAP size by growing existing Logical Volume

# Tested on RHEL 5, 6 & 7

# Check which is the swap volume and its size

root@<server>:/#> cat /etc/fstab | grep swap
/dev/rvg/swaplv         swap                    swap    defaults        0 0

root@<server>:/#> lvdisplay /dev/rvg/swaplv
--- Logical volume ---
LV Name                /dev/rvg/swaplv
VG Name                rvg
LV UUID                m0EThc-4Epd-Ecj3-lvPK-BfU0-D98H-1pgyRY
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                13.69 GB
Current LE             438
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           253:5

root@<server>:/#> free -m
             total       used       free     shared    buffers     cached
Mem:         11239       4556       6682          0        422       3697
-/+ buffers/cache:        436      10802
Swap:        14015          0      14015                                       <----

root@<server>:/#> cat /proc/swaps
Filename                                Type            Size    Used    Priority
/dev/mapper/rvg-swaplv                  partition       14352376        0       -3

# Disable swapping on LV to be resized (in our case, as we have a single LV allocated to swap, we could
# run command with '-a' flag so swapping is disabled on all known swap devices and files - as found in
# /proc/swaps or /etc/fstab)

# root@<server>:/#> swapoff -a

root@<server>:/#> swapoff /dev/rvg/swaplv

# Check that swapping has been disabled

root@<server>:/#> free
             total       used       free     shared    buffers     cached
Mem:      11508864    4657932    6850932          0     432268    3786136
-/+ buffers/cache:     439528   11069336
Swap:            0          0          0                                       <----

# Extend swap Logical Volume (we will add 1 GB)

# Verify that there is enough space on VG

root@<server>:/#> vgdisplay /dev/rvg
--- Volume group ---
VG Name               rvg
System ID
Format                lvm2
Metadata Areas        1
Metadata Sequence No 21
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                6
Open LV               6
Max PV                0
Cur PV                1
Act PV                1
VG Size               136.50 GB
PE Size               32.00 MB
Total PE              4368
Alloc PE / Size       1718 / 53.69 GB
Free PE / Size       2650 / 82.81 GB                                         <----
VG UUID               2TkcmU-Uzys-Znql-aXqx-pr2D-O8dk-oWsOlL

# Extend LV

root@<server>:/#> lvextend -L +1GB /dev/rvg/swaplv
Extending logical volume swaplv to 14.69 GB
Logical volume swaplv successfully resized

# Set up the new swap area

root@<server>:/#> mkswap /dev/rvg/swaplv
Setting up swapspace version 1, size = 15770578 kB

# Enable swapping on resized LV (in our case, as we have a single LV allocated to swap, we could
# run command with '-a' flag so swapping is enabled on all known swap devices and files (as found
# in /proc/swaps or /etc/fstab)

# root@<server>:/#> swapon -a

root@<server>:/#> swapon /dev/rvg/swaplv

# Check final size

root@<server>:/#> free
             total       used       free     shared    buffers     cached
Mem:      11508864    4664192    6844672          0     432284    3786136
-/+ buffers/cache:     445772   11063092
Swap:     15400952          0   15400952                                       <----