Re: UPS comments?

From: ac (aecnews_at_candt.demon.co.uk)
Date: 02/04/05 

Date: Fri, 04 Feb 2005 09:01:25 +0000

Brian wrote:
> On Thu, 03 Feb 2005 22:35:51 +0000, ac wrote:
>
>
>>Are you using it in a business or home environment - reason for the
>>question is that UPS's seem to be slightly rarely used, and I wonder if
>>my objectives are realistic - for a small business/home use?
>>
>
> Well, you'll know what the answer is when you have that rare power cut
> which not only looses your work, but trashes the disk too... :(
> Mine is being used on the server of a home-based network, although I may
> get another smaller one to allow graceful shutdown of the couple of
> workstations I generally work with.
>
> Ideally, I suppose, a UPS /should/ only be rarely required (if ever) but I
> feel more comfortable for having one - the last power cut here (the first
> in around 18 months) caused me to break out in a cold sweat as I dealt
> with a string of disk-related errors when the server came back up.
> I definitely don't want to go there again...
>
> I've also been involved in a business environment where almost anything
> resembling a server or machine which held important data had its attendant
> UPS - if the data reconstruction after corruption would cost 10s of
> thousands, what's £100 or so to ensure it won't happen?
>
>
>>Also I note the bottom end model (eg SU420INET) only has a serial
>>connection for control. I have seen a comment that such a connection is
>>problematic and a usb connection was recommended - in a linux context
>>
>
> KISS (Keep It Simple, Stupid)
> I was quite pleased to see the UPS I got had a serial port: serial is
> nice because it can be poked and prodded using simple tools; the data can
> be easily sniffed; it's trivial to write noddy programs to use it.
> With USB things tend to get a little too "deep" for my preferred running
> mode - instant results, and the abillity to play with easily it at a
> hardware level if I want to.
>
> If anything, I'd say that a USB device has the /capability/ of being more
> problematic in that the correct kernel modules must be installed before it
> can work, but good ol' serial ports are pretty much a rock-solid "given"
> on any machine.
> That said, if the daemon handling the UPS is happy with serial or USB as
> installed from the RPM and all you want is the functionality, it's not an
> issue. For the daemon I suggested, it's simply a case of telling it which
> interface you've used, be it serial or USB. It's also clever enough to
> check that the UPS is connected, and complain when it isn't.
>
>
>>I would be very interested to know what you expect at mainsfailure -
>>shut down or something before shutdown?
>>
>
> It can be set up in various ways, but my preferred is that when the mains
> fails (and the UPS is now holding the server up), after a certain timeout
> and if the mains hasn't since reappeared then the server is gracefully
> shut down. It's as if you were at the console doing "shutdown -h now".
> Later, after the shutdown, if the mains reappears then the server is fired
> up automatically. Of course if the mains reappears before the timeout is
> reached then the server just continues chugging away without a glitch.
>
> And talking of glitches - for the past 3 months at around 2am the mains
> supply here (20 miles north of London) drops to <190v for a few seconds,
> then pops back up to 240v. That strikes me as being a low enough dip to
> cause problems but having the UPS it's no problem at all. Mine is the
> so-called Smart-UPS, so it reports all this interesting stuff. Ok, so I'm
> easily amused too! ;)
>
> Naturally all UPS activity gets logged and warning messages are broadcast
> to any connected machines as the mains fails but that's of little
> consequence in a domestic environment with a protected server feeding
> unprotected workstations... ;)
>
> Something you'd asked for earlier and I'd not commented on: you wanted all
> open files to be neatly closed bfore the machine is shut down.
> This may not be specifically possible - it really depends on how a
> specific application behaves in response to being terminated. It might
> try to cleanly close open files as it terminates, but I suspect the action
> would be to just abandon ship as quickly as possible.
> AFAIK there's no mechanism by which an application can be told by the OS
> to save files and /then/ terminate - only that it should terminate. Happy
> to be proved wrong here!
> I think the main idea is that the equipment should be gracefully powered
> off, but the applications are left to fend for themselves.
>
> On a workstation though, it's something you can test quite easily. Set up
> an application with an open and unsaved file, then at a console issue
> "shutdown -h now" and see what's happened to the file when you restart.
>
>
> B.

Thanks Brian, much appreciated.

You mention the APC daemon. This sounds APC specific, is it (not
generic)? Is it suppplied by APC? (they do not seem to mention Linux in
their site)

The APC range is obviously good stuff. I have to decide though, about
the dabs value unit (for about a third of the price), which includes
clear mention of Linux compatibility. I have had quite good experience
with the dabs value range generally, my needs are not demanding, and
their kit seems to be generic.
(http://www.dabs.com/uk/channels/hardware/powerprotectionups/productView.htm?quicklinx=3l1t)

I am curious about UPS units which have no mention of linux - with a
serial port, say, anyway, what sort of thing would be necessary to make
good use of them with Linux? (For example, a Belkin unit) 

--
AlanC

Relevant Pages

  • Re: UPS comments?
    ... Mine is being used on the server of a home-based network, ... Ideally, I suppose, a UPS /should/ only be rarely required but I ... With USB things tend to get a little too "deep" for my preferred running ... It can be set up in various ways, but my preferred is that when the mains ...
    (alt.os.linux.suse)
  • Re: [opensuse] Question on Uninteruptable Power Supplies
    ... I wrote them asking if theirs would run under SuSE Linux and got the following and wonder if someone on this group can ... Systems CP1350AVRLCD UPS) under SuSE? ... What I mean is, when the UPS is exhausted, does the "master" server sends messages so the "slave" servers also go down cleanly? ...
    (SuSE)
  • Re: Cheap UPS for Linux?
    ... > I am looking for a cheap UPS for my linux box. ... > We have a APC UPS in the lab and it works great. ... run the computer off the main navigation 24V DC supply, which is mains ... powered with a lead-acid battery on float. ...
    (comp.os.linux.hardware)
  • Re: Spontanious SERVER shutdown (realy goes off)
    ... Server to another location in the same building without UPS. ... "Jim Behning" wrote: ... The power company installed new mains ...
    (microsoft.public.backoffice.smallbiz2000)
  • Selling LinuxCBT Redhat edition training cource .It is 75 hours/375 Videos on 10Cds training solut
    ... LinuxCBT is a unique and revolutionary approach to teaching the Linux ... outlets and other CBTs do not; real RedHat Linux skills! ... LinuxCBT includes both Client Management and Server Management ... Planning the installation - identify software, ...
    (linux.redhat)