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In the process of hibernation my laptop running Ubuntu 12.04 returns to the login screen after trying to hibernate.

When I look into the syslog I could see an error with the following message:

kernel: [34519.069373] PM: Not enough free memory
kernel: [34519.069374] PM: Error -12 creating hibernation image

Any help would be greatly appreciated.


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I'm not sure this can help you, but hibernation requires your swap partition to be at least 1.5 times your physical RAM. If not, there is not enough place in it to store the contents of your ram. If this is the case, you can try to make place by shrinking one or more of the partitions on your HD and move your partitions as needed in order to let you add the free space to your swap.

To do all these things you can use GParted from the live cd, perhaps you can even install it on your current system (but you will not be able to move mounted partitions, so it is best to work from a live session).

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Make sense, I have not tried it yet, since I have to revisit my partition and have to create enough space for the existing swap. Thanks. – RakeshS Oct 15 '12 at 7:20
With pleasure.. – Yekhezkel Yovel Oct 16 '12 at 16:46

Many people recommend having a swap partition equal to twice the RAM size. For example, if the RAM size is 8GB, then the swap space size should equal 16GB.

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I think this isn't the common recommendation today for large amounts of RAM. See link this post about Redhat's swap size recommendation, Ubuntu may have it's own recommendation. But if you have enough disk space and you want to hibernate, swap of 1.5 or 3 times your ram is the best way to get it done, because you can always end up hibernating your system when your ram is overloaded and some swap is used. It is also good to close any unnecessary programs/threads before hibernating. – Yekhezkel Yovel Oct 16 '12 at 16:54

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