Shutdown forced by UPS

[franconi]

Hi,
The following seems a common scenario for may of us.
I have a UPS that forces a shutdown when the current goes off and the UPS battery is low. How does SD behave in this case, if this happens while SD is making the backup? Is the backup copy left in an incomplete but safe (i.e., readable) state, or is the copy screwed up? I am making the backup to a single disk image in a networked NAS disk.
What would be the best way to handle such case?
cheers
--e.

[dnanian]

Well... it really depends on how the UPS software does the shutdown. If it's a clean shutdown, everything should be safe but incomplete. If it's a "bad" shutdown, nearly anything could happen.

[franconi]

Originally Posted by dnanian

Well... it really depends on how the UPS software does the shutdown. If it's a clean shutdown, everything should be safe but incomplete. If it's a "bad" shutdown, nearly anything could happen.

Well... http://www.shirt-pocket.com/forums/i...lies/smile.gif
It is a typical Mac built-in forced shutdown: it does not depend on the UPS software, but it is the built-in UPS management software of MacOSX Tiger.
Since 10.4.9, Intel Macs (like mine) have a "shutdown -u" option (see man shutdown), that is actually used for UPS forced shutdowns (see the script /usr/libexec/upsshutdown).

So, given the above info, can you comment whether SD will leave the remote disk image safe (i.e., readable although incomplete) after an UPS shutdown?

cheers
--e.

[dnanian]

Give what that script does -- force a shutdown -- it's unlikely an image would be unmounted by Finder before power was removed (since it waits for a dirty close).

[franconi]

Originally Posted by dnanian

Give what that script does -- force a shutdown -- it's unlikely an image would be unmounted by Finder before power was removed (since it waits for a dirty close).

Since we have the possibility to edit/personalise the script in /usr/libexec/upsshutdown, what would you do to manage the whole process properly from the SD point of view, before launching the final shutdown -h?

cheers
--e.

[dnanian]

Well, I'd probably try to kill SDCopy and unmount the image, if any.