LVM: Extend SWAP size by adding a new Logical Volume -

LVM: Extend SWAP size by adding a new Logical Volume

# Tested on RHEL 5, 6 & 7

# Adding a file to swap space is not a common operation so we will focus on adding a LV

# Check current swap volume(s) 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

# Create a new Logical Volume, preferably on system VG, that will be dedicated to swap space

# We will extend swap by adding a 1 GB Logical Volume

# 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 23
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

# Create new LV

root@<server>:/#> lvcreate -L 1GB -n newswaplv rvg
Logical volume "newswaplv" created

# Check LV

root@<server>:/#> lvdisplay /dev/rvg/newswaplv
--- Logical volume ---
LV Name                /dev/rvg/newswaplv
VG Name                rvg
LV UUID                gf2IqR-kRMj-vMnJ-VCH3-N0gh-UxoG-AWX6Xu
LV Write Access        read/write
LV Status              available
# open                 0
LV Size                1.00 GB
Current LE             32
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           253:6

# Set up the new swap area

root@<server>:/#> mkswap /dev/rvg/newswaplv
Setting up swapspace version 1, size = 1073737 kB

# Enable swapping on new LV

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

# Check final size and partitions being used by swap

root@<server>:/#> free
             total       used       free     shared    buffers     cached
Mem:      11508864    4664996    6843868          0     432464    3786168
-/+ buffers/cache:     446364   11062500
Swap:     15400944          0   15400944                                       <----

root@<server>:/#> cat /proc/swaps
Filename                                Type            Size       Used    Priority
/dev/mapper/rvg-swaplv                  partition       14352376      0       -5
/dev/mapper/rvg-newswaplv               partition       1048568       0       -6    <----

# Add following line to /etc/fstab for the LV to be automatically mounted as swap
# during system startup

/dev/rvg/newswaplv         swap                    swap    defaults        0 0