Linux divides its memory into chunks called pages. The
process of copying a page of memory onto a hard disk is called swapping. This
is typically on its own partition called swap space.
The benefits of swapping memory pages to disk, is that the
total available amount of virtual memory on a system can be increased.
Typically inactive applications which aren’t immediately in need of memory will
have some of their pages swapped to disk, allowing for active applications to
have speedier access to memory.
The downside to swapping is that is much slower than actual
RAM and can be thousands of times slower. If too much memory is swapped, it can
lead to a slowdown of your system because of excessive read/write operations on
the hard disk.
Currently on our Virtual Private Servers, swap space is
disabled. However we are looking in to providing virtual swap space, with their
own dedicated storage so we can have all the benefits of swap space, with few
of the downsides.