Expanding a Swap Partition

Before You Begin 

Make sure you know the name of the swap volume and the KeyControl clear text path to it. If you do not, use the hcl status command and look at the Registered Devices section. For example:

# hcl status
...

Registered Devices
--------------------------------------------------------------------------------
Disk Name     Cipher       Status                 Clear 
--------------------------------------------------------------------------------
sda3         AES-256      Attached                /dev/mapper/clear_htswap (swap)
 '--> auto_attach=ENABLED, attach_handler=DEFAULT, detach_handler=DEFAULT
sda2            AES-256      Attached                 /dev/mapper/clear_htroot (/)
 '--> auto_attach=ENABLED, attach_handler=DEFAULT, detach_handler=DEFAULT

Procedure 

1. Log into the VM as root.

2. Get the UUID of the swap device by using the blkid swap-clear-text-path command. For example:

   # blkid /dev/mapper/clear_htswap
   /dev/mapper/clear_htswap: UUID="62e5b7ca-cc50-409f-ba7d-5f0645c85588" TYPE="swap"

3. Turn the swap off by entering the command swapoff -a.

   # swapoff -av
   swapoff on /dev/mapper/clear_htswap

   Tip:

   If the swapoff command does not work, applications are probably using the swap file. You can make a temporary swap space and move the swap there until this procedure is finished. For example:

   # fallocate --length 2GiB /swapfile
   # mkswap /swapfile
   # swapon /swapfile

   You can also try dropping stopping all main applications and then dropping all caches from memory. For details, see your Linux documentation.

4. Increase the size of the swap device as desired. How you do this depends on the partition type.

   • If this is a GPT partition, you can use parted as long as you preserve the GUID assigned to the GPT partition. To determine the GUID, use the i partition-number command and look at the "Partition unique GUID" field. For an example of setting the GUID on a GPT partition, see Expanding a Linux Data Partition.
   • If this is a non-GPT partition, you can use the fdisk diskname command, where diskname is the name of the swap device. An example of this process follows.
   Non-GPT Partition Example

   For example, if you want to increase the non-GPT swap partition sda3 by 256M, you would enter:

   # fdisk /dev/sda
   
   WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
            switch off the mode (command 'c') and change display units to
            sectors (command 'u').
   
   Command (m for help): p
   
   Disk /dev/sda: 17.2 GB, 17179869184 bytes
   255 heads, 63 sectors/track, 2088 cylinders
   Units = cylinders of 16065 * 512 = 8225280 bytes
   Sector size (logical/physical): 512 bytes / 512 bytes
   I/O size (minimum/optimal): 512 bytes / 512 bytes
   Disk identifier: 0x000a3126
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/sda1   *           1         131     1048576   83  Linux
   Partition 1 does not end on cylinder boundary.
   /dev/sda2             131        1828    13631488   83  Linux
   /dev/sda3            1828        1980     1223262   82  Linux swap / Solaris
   
   Command (m for help): d
   Partition number (1-4): 3
   
   Command (m for help): n
   Command action
      e   extended
      p   primary partition (1-4)
   p
   Partition number (1-4): 3
   First cylinder (1828-2088, default 1828):
   Using default value 1828
   Last cylinder, +cylinders or +size{K,M,G} (1828-2088, default 2088):
   Using default value 2088
   
   Command (m for help): t
   Partition number (1-4): 3
   Hex code (type L to list codes): 82
   Changed system type of partition 3 to 82 (Linux swap / Solaris)
   
   Command (m for help): p
   
   Disk /dev/sda: 17.2 GB, 17179869184 bytes
   255 heads, 63 sectors/track, 2088 cylinders
   Units = cylinders of 16065 * 512 = 8225280 bytes
   Sector size (logical/physical): 512 bytes / 512 bytes
   I/O size (minimum/optimal): 512 bytes / 512 bytes
   Disk identifier: 0x000a3126
   
      Device Boot      Start         End      Blocks   Id  System
   /dev/sda1   *           1         131     1048576   83  Linux
   Partition 1 does not end on cylinder boundary.
   /dev/sda2             131        1828    13631488   83  Linux
   /dev/sda3            1828        2088     2090772   82  Linux swap / Solaris
   
   Command (m for help): w
   The partition table has been altered!
   
   Calling ioctl() to re-read partition table.
   
   WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
   The kernel still uses the old table. The new table will be used at
   the next reboot or after you run partprobe(8) or kpartx(8)
   Syncing disks.

5. Run the partprobe command to reread the partition table. If this command fails because the device is busy, you need to reboot the VM.

   # partprobe /dev/sdb
   Warning: WARNING: the kernel failed to re-read the partition table on /dev/sda (Device or resource busy).  As a result, it may not reflect all of your changes until after reboot.
   
   # reboot

6. If you had to reboot the VM in the previous step, turn the swap off again by entering the command swapoff -a.

   # swapoff -av
   swapoff on /dev/mapper/clear_htswap

7. Recreate the swap device with the same UUID as the old device and turn it back on. For example:

   # mkswap -U "62e5b7ca-cc50-409f-ba7d-5f0645c85588" /dev/mapper/clear_htswap
   mkswap: /dev/mapper/clear_htswap: warning: don't erase bootbits sectors
           on whole disk. Use -f to force.
   Setting up swapspace version 1, size = 2090768 KiB
   no label, UUID=62e5b7ca-cc50-409f-ba7d-5f0645c85588
   # swapon -a
   
   # swapon -s
   NAME      TYPE      SIZE      USED PRIO
   /dev/dm-3 partition 2090768   0    -1