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I'm using 2 GB RAM I've installed Ubuntu 14.04 LTS how much swap do I need to create?

Braiam
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Swapnil
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    Welcome to Ask Ubuntu! Please modify your question to add additional information. – Tim Jul 10 '14 at 14:57

4 Answers4

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There is varying opinion on what the size of the swap should be - here are the Example Scenarios provided in the Ubuntu wiki:

RAM(MB) No hibernation  With Hibernation        Absolute maximum
 256     256              512                     512
 512     512             1024                    1024
1024    1024             2048                    2048

RAM(GB) No hibernation  With Hibernation        Absolute maximum
  1      1                2                       2
  2      1                3                       4
  3      2                5                       6
  4      2                6                       8
  5      2                7                      10
  6      2                8                      12
  8      3               11                      16
 12      3               15                      24
 16      4               20                      32
 24      5               29                      48
 32      6               38                      64
 64      8               72                     128
128     11              139                     256

Here also a table from the Fedora 64bit docs:

For <2GB, it recommends the swap should be '3 times the amount of RAM' in size.

This mainly depends if you need want to hibernate or not - you need more as it saves the state of the system from the RAM to the swap.

Note swap may slow things down if swappiness is not configured correctly - you can read this question to find out how to do it.

If you need to increase the size of (or create) swap space, there are a few nice answers here.

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Wilf
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    The Ubuntu one is here: https://help.ubuntu.com/community/SwapFaq - it doesn't have a neat table, but then again, I prefer text to images. – muru Jul 11 '14 at 21:55
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For small RAM sizes like 1 or 2 or 3 GB its better to create a swap partition with double the size of RAM. eg: 4GB in your case. For rams higher like 8 GB swap partition of 2 GB will be sufficient.

Sudheer
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    Please see: http://askubuntu.com/questions/49109/i-have-16gb-ram-do-i-need-32gb-swap Personally i HAVE 2gb OF ram in this machine and 1GB of swap and have never run out. The double RAM Swap idea is a myth perpetuated by windows due to it's poor memory management. 'nix systems are much more RAM efficient. That being said a lot depends on what you are doing with the system. Video editing requires more ram than browsing the web, playing youtube videos and checking your email. – Elder Geek Jul 10 '14 at 14:41
  • @Elder Geek- yes seems true but hibernation do requires high swap space. – Sudheer Jul 10 '14 at 14:50
  • That's a good point. I never use it. I turn things off when I'm not using them. – Elder Geek Jul 10 '14 at 14:58
  • @Elder Geek- what would be the minimum swap space for hibernation – Sudheer Jul 10 '14 at 14:59
  • @Sudheer how I can create swap in currently installed drive or root? – Swapnil Jul 10 '14 at 14:59
  • @Sudheer As I never use it, My best guess in this instance would be 3GB – Elder Geek Jul 10 '14 at 15:01
  • @user73898 you should create a separate partition for swap. – Sudheer Jul 10 '14 at 15:01
  • @Elder Geek- I never used it but, want to try it sometime. Thank you for your replies. – Sudheer Jul 10 '14 at 15:02
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    @Sudheer Not true, you can create a swap file on an existing partition. – fkraiem Jul 10 '14 at 15:03
  • @user73898 That's a different question. Look here: https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-14-04 – Elder Geek Jul 10 '14 at 15:05
  • I have 12 Gb RAM - and I don't have any swap. I think of my RAM as if I had 8 Gb RAM and 4 Gb of fast swap :) In fact required swap depends on the computer usage. I don't think that having swap is really good idea in era when memory is one of the most cheepest pc components. – Sergey P. aka azure Jul 10 '14 at 20:20
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Personally I always make my swap 512 MB, just to have some wiggle room. If the OS starts using a lot of swap, you really need more RAM. (And if getting more RAM is not an option, then you can consider having more swap, it's better than nothing.)

fkraiem
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4GB.

Without additional information we can't be specific, so I'm erring on the larger side: 4GB is probably more than you need, and disk space is cheap.

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thomasrutter
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