LVM: Reduce SWAP size by shrinking existing Logical Volume

LVM: Reduce SWAP size by shrinking 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                14.69 GB
  Current LE             470
  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       4555       6683          0        422       3697
-/+ buffers/cache:        435      10803
Swap:        15039          0      15039                                     <----


root@<server>:/#> cat /proc/swaps
Filename                                Type            Size    Used    Priority
/dev/mapper/rvg-swaplv                  partition       15400952        0       -4



# 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    4657068    6851796          0     432316    3786148
-/+ buffers/cache:     438604   11070260
Swap:            0          0          0                                     <----


# Reduce swap Logical Volume (we will remove 1 GB)

root@<server>:/#> lvreduce -L -1GB /dev/rvg/swaplv
  WARNING: Reducing active logical volume to 13.69 GB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce swaplv? [y/n]: y
  Reducing logical volume swaplv to 13.69 GB
  Logical volume swaplv successfully resized



# Set up the new swap area

root@<server>:/#> mkswap /dev/rvg/swaplv
Setting up swapspace version 1, size = 14696837 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    4664880    6843984          0     432320    3786160
-/+ buffers/cache:     446400   11062464
Swap:     14352376          0   14352376                                       <----
0 (0)
Article Rating (No Votes)
Rate this article
Attachments
There are no attachments for this article.
Comments
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
How To Add Swap Space on Ubuntu 16.04
Viewed 2570 times since Fri, Jun 8, 2018
Check a Website Availability from the Linux Command Line
Viewed 6891 times since Mon, Feb 18, 2019
15 Linux Yum Command Examples – Install, Uninstall, Update Packages
Viewed 3660 times since Thu, Oct 25, 2018
How to Register and Enable Red Hat Subscription, Repositories and Updates for RHEL 7.0 Server
Viewed 13403 times since Mon, Oct 29, 2018
logrotate Log Rotate Configuration
Viewed 3396 times since Sun, Jan 12, 2020
What Is /dev/shm And Its Practical Usage
Viewed 8334 times since Tue, Mar 12, 2019
Linux Find Large Files
Viewed 3128 times since Mon, Oct 29, 2018
How log rotation works with logrotate
Viewed 5115 times since Fri, Nov 30, 2018
Linux - How to perform I/O performance test with dd command
Viewed 6293 times since Fri, Jun 8, 2018
Linux get the list of FC HBA’s and WWPN
Viewed 3723 times since Tue, May 22, 2018