Swap Space is used on Unix and Linux systems to provide additional pseudomemory resources. In other words, if you try to run so many processes that they won't all fit into memory at the same time, the operating system will swap them in and out of the swap space.

Swap space can be either disc partition(s) (a.k.a. slice(s)) dedicated to the task, and/or file(s) held within the file system. Although the operating system will attempt to swap as efficiently as possible, it does turn into a heavy resource burden sometimes and it's worth tuning your file system layout to take note of this:
a) Use Swap partitions rather than files (but files are great for a temporary expansion if you need it)
b) If you have multiple disc drives of the same speed, spread the swap area between them
c) If you have multiple disc drives of different speeds, put you swap space on the fastest
d) Keep the swap space in the middle of the disc / close to often used files to mimimise head movements
e) If you are using network drives, do NOT put any swap space onto a remote drive!

(written 2004-12-16, updated 2006-06-05)

 A162 - Web Application Deployment - Backups and File System Management
  [334] Symbolic links and hard links - (2005-06-02)
  [554] What backup is adequate? - (2006-01-04)
  [593] Finding where the disc space has gone - (2006-02-06)
  [703] Copying files and preserving ownership - (2006-04-28)
  [735] Boys will be boys, saved by Ubuntu - (2006-05-27)
  [754] tar, jar, war, ear, sar files - (2006-06-10)
  [1013] Copy multiple files - confusing error message from cp - (2006-12-30)
  [1023] Finding public writeable things on your linux file system - (2007-01-06)
  [1288] Linux run states, shell special commands, and directory structures - (2007-08-03)
  [1439] Linux / Unix - layout of operating system files - (2007-11-20)
  [1648] The tourists guide to Linux - (2008-05-20)
  [1765] Dialects of English and Unix - (2008-08-21)
  [1801] Will your backups work if you have to restore them? - (2008-09-18)
  [1893] Some Linux and Unix tips - (2008-11-18)
  [2299] How much space does my directory take - Linux - (2009-07-20)
  [4056] An overpractical test of our backup strategy! - (2013-03-30)
  [4063] Backups by crossover between network centres - setting up automatic scp transfers - (2013-04-13)
  [4115] More or less back - what happened to our server the other day - (2013-06-14)
  [4390] Checking MySQL database backups have worked (not failed) - (2015-01-10)
  [4400] Commenting out an echo killed my bash backup script - (2015-01-19)
  [4405] Backup procedures - via backup server - (2015-01-24)
  [4481] Extracting data from backups to restore selected rows from MySQL tables - (2015-05-01)

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