Has anyone played with different hibernation modes?

Apparently Mac OS X has three hibernation modes (as outlined below from an official Apple document): a. Always save the RAM content to HD and hibernate (this is the default), b. Dont save RAM content to HD (I think this is the "regular sleep" and risks losing data if power is interrupted), and c. Save RAM content to HD and hibernate when the battery power is at a critical level.

I am planning to change the default scenario (point (a) above) to the (c) to avoid writing RAM content to HD every time the lid is closed. Has anyone changed the hibernation modes before? If so, has there been any problems with battery life, data loss, etc etc?

Thanks in advance!

 

I see no reason to change them...

by default, everything is saved for default sleep. If the battery is critically low, then it writes it all to the drive and physically turns off.... when you start back up you get a little white bar progress on the gray screen as it resumes back where it left off. Its slower to start up than a normal sleep, but it doesn't use any battery power that way.

using method "b" would barely increase speed at all, with a risk of problems. I think Apple's defaults are the best choice.

 

Thanks for the reply. I just wanted to make sure that the "default" doesn't write to the disk as long as there is power. For some reason I thought that the default was the scenario where the RAM content was written to the disk at every sleep. Doesn't seem like it...

By the way, I am not doing this to increase "speed"; I am trying to avoid unnecessary use of the SSD by the safe sleep process.

 

no... the RAM contents are stored to disk on every sleep, but its not a full shut down hibernation... it only does that if it doesn't have enough power.

It doesn't store them exactly the same in both ways...

you can go in and make it where normal sleep never saves any RAM states, and hope for the best, but its more prone to problems, so Apple stopped using it.

 

I see.... So, the default stage DOES write RAM stage to the disk whether it ends up being of full shutdown hibernation. Since I rarely put my MBP to sleep, I am try setting it to "0" and see what happens. If it creates any problems, I can always go back, right?

Thanks!

 

it usually seems to work if you make it not save the ram state... theres just times corruption can occur and screw up waking back up, but thats pretty rare. Also if the machine loses power while asleep and it has to restart, things can get corrupted easier.. causing minor to major issues depending what happened.

 

I changed the sleep state to mode 0 (keep everything in RAM and dont save anything to HD) about 5 days ago. I've tried many different cycles of sleep/wake up (e.g., closing the lid, putting into sleep from the menu, letting it go to sleep after certain minutes, waking up from the attached peripherals, over the network, etc) and everything is working fine so far...

 

Personally, I think the defaults are a good balance of usability and security. The always-hibernate option is as annoying as setting a 'hibernate on close lid' under Windows XP for example, while the memory-only approach is only a little less battery-sapping in the long run (although you could make the argument that you need all the runtime you can eke on the overrated - 8 hours my butt - unibodies), and more prone to issues in daily use.

 

The only reason I changed the sleep profile to "keep in RAM only without writing to HD" is to decrease the writing of RAM content to SSD every time the computer goes to sleep. In addition, clearing up the sleep image released additional 4GB of space