I have an early Early 2011 MBP, which I installed 16GB of RAM in, despite the fact that Apple claims the maximum is 8GB. This is a hack which is known to work, but I'm having some trouble with hibernate as a result.
It seems my sleep image is only 8GB, despite the fact that my RAM is 16GB; consequently, if I lose power while having more than 8GB in memory, safe sleep fails.
Any ideas on how to correct this?
See whether the problem is reproducible with compressed memory disabled.
If that's not a workaround, please vote down this answer and leave a comment.
vm_compressor_mode (vm.compressor_mode) values for enabled compressed memory in OS X
– there's a link to an answer about disabling compressed memory.
I have exactly the same configuration (MacBook Pro Early 2011 16GB/10.7.5 though) and my sleepimage has full 16 GB size.
Just delete it by opening Terminal (located in /Applications/Utilities), and typing in the following command, followed by the enter key:
sudo rm /private/var/vm/sleepimage
Enter your administrator password (it will not be visible) and hit the enter key again.
Your Mac will automatically rebuild it when needed (hopefully with the correct size).
Recently I experiment a lot with disabling memory compression in Mavericks and I had clearly reproducible problems with hibernating to disk.
1) Enable memory compression and using an hibernate mode that writes to disk works without problems
vm_compressor=4 + hibernatemode=3(RAM powered+sleepimage) or 25(only sleepimage)
-> no problem when restored from sleepimage
2) Disable memory compression and using an hibernate mode that writes to disk leads to kernel panics when waking up.
vm_compressor=1 + hibernatemode=3(RAM powered+sleepimage) or 25(only sleepimage)
-> kernel panic when restored from sleepimage
3) Disable memory compression and using an hibernate mode that NOT writes to disk works fine.
vm_compressor=1 + hibernatemode=1(only RAM powered)
-> no problem, as long you have enough battery power
to prevent lost of RAM while sleeping
Well 3) is only a compromise since it lets you disable the memory compression, but you will loose the safety of the sleepimage.
