Sleep and Shutdown question

Discussion in 'macOS' started by netnothing, Aug 28, 2007.

  1. netnothing macrumors 68040


    Mar 13, 2007
    I originally posted this in the Mac Pro forum....but since it's not really machine specific, I figured I'd post over here to see if anyone knows:

    So I just got a new UPS for my Mac Pro and I'm using OS X's built in Power Mgmt.

    Here's a question, if I set the Mac Pro to go into Sleep mode after XX minutes on battery, what possible damage could be done if the UPS battery runs out of juice and shuts the machine off before the power returns?

    I guess my issue is I'd rather have it go into sleep instead of a full shutdown for the outages that just last an hour or so....but if it should last for many many hours, the battery will eventually die and the Mac Pro will shut down....but not peacefully. Of course this is all when I'm physically not here.

    So does a non-graceful shutdown from sleep mode pose a greater risk of damage to the system? software wise? hardware wise?

    I guess hardware wise it shouldn't because everything is spun down. But software wise, you'd lose any work in open apps....although I guess the same would happen if I let OS X shut itself down when I'm not here. OS X better at not getting corrupted than Windows on non-graceful shutdowns? Is it the fact that OS X uses a Journaling file system that helps it?

  2. mkrishnan Moderator emeritus


    Jan 9, 2004
    Grand Rapids, MI, USA
    I'm curious to hear input on this also. I think you're essentially right...

    - hardware wise, slightly better, as more things are powered down already.
    - active apps -wise, same
    - overall software / data integrity-wise, better -- because your hard drive is not spun up, there's no chance that it's being shut down in the middle of doing a data write or anything like that. Although the journal should be able to fix the hard drive automatically, this should still mostly eliminate the chance that your computer will come back up with a logical structure / filesystem issue (e.g. that would need to be corrected by the repair disk item in Disk Utility).

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