RHEL 6 Storage Admin - 14.2. Adding Swap Space

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14.2. Adding Swap Space

Sometimes it is necessary to add more swap space after installation. For example, you may upgrade the amount of RAM in your system from 128 MB to 256 MB, but there is only 256 MB of swap space. It might be advantageous to increase the amount of swap space to 512 MB if you perform memory-intense operations or run applications that require a large amount of memory.

You have three options: create a new swap partition, create a new swap file, or extend swap on an existing LVM2 logical volume. It is recommended that you extend an existing logical volume.

14.2.1. Extending Swap on an LVM2 Logical Volume

By default, Red Hat Enterprise Linux 6 uses all available space during installation. If this is the case with your system, then you must first add a new physical volume to the volume group used by the swap space. For instructions on how to do so, refer to Section 3.2.2, “Adding Unallocated Volumes to a Volume Group”.

After adding additional storage to the swap space's volume group, it is now possible to extend it. To do so, perform the following procedure (assuming /dev/VolGroup00/LogVol01 is the volume you want to extend by 256MB):

Disable swapping for the associated logical volume:

swapoff -v /dev/VolGroup00/LogVol01
Resize the LVM2 logical volume by 256 MB:

lvresize /dev/VolGroup00/LogVol01 -L +256M
Format the new swap space:

mkswap /dev/VolGroup00/LogVol01
Enable the extended logical volume:

swapon -v /dev/VolGroup00/LogVol01

To test if the logical volume was successfully extended, use cat /proc/swaps or free to inspect the swap space.