10.4 Hibernation problem

[isantop]

Just don't hit yourself too hard. That would hurt!

[bill516]

We just might have a solution, but I am not ready to mark this thread "solved" just yet.

An effort to make the Ubuntu swap partition larger by shrinking the Home partition failed when GParted left Home in a corrupted state.

At that point it was simpler to remove and reconstruct both the Home and Swap partitions.

Readers: Good reason to back up before you do anything like this. My own data files are on another partition entirely. Home holds only configuration and a few "working" files not yet moved over to my Documents partition.

This gave me a swap partition at just under 5 gigabytes for a machine with 3 gigabytes of RAM.

And the system would not hibernate.

Time for nuclear weapons. Both Ubuntu and Mepis were blown out completely. Only Ubuntu has been reinstalled. The new swap file is now 6.8 gigabytes. (I am not smart. I am mostly stubborn.)

Good news!

This new installation does hibernate, but neither the System 76 driver nor the proprietary Nvidia driver are installed.

I will install these one at a time and test suspend/hibernate with each.

I'll report back when I have finished.

Unless I knock myself silly with that hammer.

[bill516]

We can now mark this thread as solved. Ubuntu 10.4 64 bit will both suspend and hibernate properly.

Recall the initial problem: It appeared that the system would suspend to RAM (or "suspend") quite normally. It would not suspend to disk (or "hibernate"). It seemed to enter the hibernated state properly, but it would not come back up with the saved desktop or an operational wireless connection.

There are several ways this might happen. So if an inability to hibernate your system is driving you around the bend try these steps.

1. Ubuntu uses UUIDs to track the several partitions it uses. These are stored in the file /etc/fstab. Suggestion: use the command "sudo blkid" to print a list of partitions and the UUIDs associated with them. Check these against the UUIDs shown in /etc/fstab. They must agree. If they do not hibernation will not work. The UUIDs in etc/fstab must match those reported by blkid. If they do not then it is a simple matter to use gedit and do a bit of editing.

2. Now go to /etc/intramfs-tools/conf.d/resume. You should see an entry there which looks something like this: "RESUME=UUID=59d93a99-54da-4a6a-9360-b97f370288c1" Whatever it is it must be the same UUID reported by blkid for the swap partition being used by Ubuntu. This also is the same swap partition UUID listed in /etc/fstab.

Hibernation relies upon the location data in etc/fstab in order to place the saved desktop into the proper swap partition. But it needs that same UUID in /etc/intramfs-tools/conf.d/resume in order to find the information it placed in the swap partition earlier.

No, I am not smart enough to figure this out and I am indebted to v41 for his very important contribution on this point. I did not know there was such a thing as a "resume" file!

But hibernation still will not work if the swap file is not large enough to hold the material which must be saved. On this point isantop's suspician turned out to be right; my swap file simply was not large enough.

So how large must it be? My system has 3 Gigabytes of installed RAM. A swap of that size was not enough. Similarly a swap on the order of 5 Gigabytes was not enough. In several trials with swap partitions of 3 & 5 gigabytes hibernation consistently failed.

My present swap file is 6.8 gigabytes, which is far in excess of what I frequently see suggested as necessary. My experience tells me I will not run anything smaller. In short do your swap as twice your installed RAM and a bit more. Look at it this way, we are going to use less than 2% of a nominal 500 gigabyte HD to stay out of trouble. Most laptop owners, in particular, will gladly make the trade!

So if hibernation does not work pay very close attention to UUIDs, which are very important. Then be generous with the size of the swap file used by the system.

Neither the proprietary Nvidia driver nor the System 76 driver appear to have any bearing at all on this problem.

When I come out of hibernation my wireless connection is operational with no further intervention needed.

I do show a dim screen when I come out of hibernation and so I must bring it to full brightness using Fn-F9. I do not regard that as serious.

One last point: Be careful about using GParted to manipulate your partitions. An apparent GParted failure caused my Home partition to be corrupted and required that I reinstall my system. (No, the partitions were not mounted when I worked on them.) If you are going to manipulate a partition with GParted do back it up first!

My sincere thanks to isantop and V41 for their help with this problem. I could not have worked this through without their considerable expertise and their willingness to share it.

[isantop]

Good to see you had that worked out.

To clarify on the GParted issue:

Always right click and select "swapoff" in GParted for each swap partition you have before doing any work on your disk. Not doing so may result in Data loss.

Even if you have done this, make sure to backup your data before messing with partitions. It is faster to backup and rebuild than to try and recover data from a hosed partition or Filesystem. Random errors can occur, and you still have to take into account the possibility of battery/power failure, sudden shock/force, etc.