[3907] in RedHat Linux List
Re: UPS reccomendations
daemon@ATHENA.MIT.EDU (David Myers)
Mon Nov 11 15:26:39 1996
From: David Myers <dem@netsco.com>
To: redhat-list@redhat.com
Date: Mon, 11 Nov 1996 15:21:19 -0500 (EST)
Resent-From: redhat-list@redhat.com
Reply-To: redhat-list@redhat.com
Mike Schout wrote:
> If your referring to apcd, which is what we are using with our APC smart
> UPS's, I dont see a problem with it. It does not completely HALT the os,
> but it comes about as close to it as possible. It turns off networking,
> unmounts file systems (this is the important one), and then will turn the
> UPS off. I think that the reason it doesnt completely halt the OS is
> because it needs to still send the signal to turn off the UPS.
If the shutdown process bypasses the normal shutdown sequence
carried out by init, then running programs may not be shut down
correctly (because the files /etc/rc.d/rc0.d/K* won't be run).
This can lead to things like corrupt databases.
A Smart-UPS can be commanded to power down after a programmable
delay. Alternately, the command can be sent from a command-line
program called at the end of /etc/rc.d/init.d/halt (I do this
with the Back-UPS I use at home, as the Back-UPS doesn't have the
delay feature).
Richard Bullington wrote:
> In apcd-0.5, the source code for do_shutdown is crystal clear. It signals
> the UPS to shut down, then initiates a regular shutdown via calling
> "/sbin/shutdown now -hft 2" , which will halt the system after only a few
> seconds in most cases.
Aha! There seem to be two programs called apcd-0.5 out there.
In the copy I have, do_shutdown() uses code extracted from the
"shutdown" program from linux-utils. I wonder which of the two
ended up in the binary RPM.
Still, the proper procedure is to notify init of the power failure
(example code to do this is in powerd.c in the SysVinit SRPM).
This allows the user to tailor the shutdown delay and the message
broadcasted to all users by editing the appropriate line in
/etc/inittab.
Daniel Senie wrote:
> APC has no interest in supporting Linux. I've talked with them. They claim
> that their "protocol" is proprietary information and they will not give it
> out. The code in APCD will wind up being your best bet.
An APC support person told me:
> The Smart-UPS UPSLink language is available for license. If you are
> interested, please let me know and I will get the procedure under way. APC
> requires that you sign a non-disclosure agreement in order to license the
> language (this does not hamper your ability to distribute your software or
> source code).
I asked them to clarify and am awaiting a response.
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