[Nut-upsdev] Suspend-to-disk & NUT

[Arjen de Korte]

Charles Lepple schreef:

> You may be breaking new ground here - I would guess that most people
> who are using suspend-to-disk are using laptops, and would find the
> UPS monitoring redundant. (However, I have heard of why this is useful
> for servers.)

For the record, this is a desktop system and I was just trying to see if
I can get the suspend-to-disk to work. It does seem to save quite a
considerable amount of time on startup, so in the past two weeks I have
found it to be a very useful feature. I intend to use this on a server
too, once I have worked out the problems I see now, since it speeds up
restarting after a power outage.

> I haven't used suspend-to-disk much myself, but I think you might be
> able to get some useful information from the driver if you tell strace
> to attach to it before suspending. (Options such as '-t' can help you
> correlate the logs to pre- and post-suspend time.)

I'll probably first try to insert some code in the SafeNet driver which
communicates with the UPS attached to this system, to see whether the
problem is related to the communication with the UPS or somewhere else
in NUT.

> Also, is this the kernel suspend-to-disk system, swsusp2, or something
> else?

It is done via powersave (http://powersave.sourceforge.net/) which uses
swsusp to store the state of the machine in the swap partition.

> It might depend on how the processes are put to sleep. The
> kernel version would also be useful.

I'm using a stock SuSE 9.3 kernel ('uname -r' reports
2.6.11.4-21.10-default right now).

Regards,
Arjen