[K12OSN] Uninteruptable Power Supply UPS with Linux

Tue Oct 17 05:02:44 UTC 2006

On 10/16/06, James P. Kinney III <jkinney at localnetsolutions.com> wrote:
>
> On Mon, 2006-10-16 at 13:04 -0600, Calvin Dodge wrote:
> > On 10/16/06, Robert Arkiletian <robark at gmail.com> wrote:
> > >
> > >
> > >  Why do you recommend usb over serial?
> >
> > The cheaper APCs don't do true serial communication (i.e., sending
> > data to the computer). Instead, they set certain signals (like CTS,
> > IIRC) to indicate their condition.
>
> It even more complicated than that. The different models transmit
> differing amounts of data. Whether the data port is serial or usb makes
> no difference. The Back-UPS vs the Smart-UPS have a large amount of
> functionality difference. The Backups is simpler and has only a timer
> function. Once it goes on battery, the timer starts. At the end of the
> timer, it send the shutdown command to the host.
>
> The smartups has much more of a command set. It supports battery
> condition testing and and can signal a power down when the battery falls
> below a certain level. More importantly, it can hold of on powering back
> up until the battery has reached a certain minimum runtime level.
>
> On my current install, we have Smart-UPS XL 3000VA RM 3U models that
> have both serial and USB connectors. The same data is on both ports.
>
> One nice thing about these (and all Linux systems can be setup to do
> this) is when the shutdown command is issued, the apcupsd can be told to
> also send it to a group of other machines. In my current case, there are
> several servers that run off the UPS in the rack. If the UPS is going
> down that powers the main login/NFS-/home machine, every other server
> will need to also shut down as they will have nothing they can do. If a
> UPS signals to a boot/app server the remaining app servers can stay up.
>
> So the UPS is told power back up when the AC as back and the batteries
> are back up to enough time to allow a partially booted system to shut
> down gracefully. The first box up is the NFS server. It will then tickle
> the other machines with Wake-on LAN calls (as soon as I can finish that
> process).

Wow nice info James. Thanks. I really like the fact that one box can tell
the others to shutdown also. Is this done by setting up ssh keys? There must
be some kind of auth required.

>
> > USB allows for real communication with the host computer, and I
> > _believe_ that means real data gets sent to that host. For example,
> > here's the output of "apcaccess" on my workstation:
> >
> > APC      : 001,034,0890
> > DATE     : Mon Oct 16 12:59:50 MDT 2006
> > HOSTNAME : source-server.prosocial.local
> > RELEASE  : 3.12.4
> > VERSION  : 3.12.4 (19 August 2006) redhat
> > UPSNAME  : source-server.prosocial.local
> > CABLE    : USB Cable
> > MODEL    : Back-UPS NS 600
> > UPSMODE  : Stand Alone
> > STARTTIME: Fri Oct 13 13:05:46 MDT 2006
> > STATUS   : ONLINE
> > LINEV    : 118.0 Volts
> > LOADPCT  :   0.0 Percent Load Capacity
> > BCHARGE  : 100.0 Percent
> > TIMELEFT :  42.8 Minutes
> > MBATTCHG : 5 Percent
> > MINTIMEL : 3 Minutes
> > MAXTIME  : 0 Seconds
> > LOTRANS  : 088.0 Volts
> > HITRANS  : 139.0 Volts
> > ALARMDEL : Always
> > BATTV    : 13.5 Volts
> > LASTXFER : Low line voltage
> > NUMXFERS : 0
> > TONBATT  : 0 seconds
> > CUMONBATT: 0 seconds
> > XOFFBATT : N/A
> > STATFLAG : 0x07000008 Status Flag
> > MANDATE  : 2005-12-26
> > SERIALNO : 3B0601X00177
> > BATTDATE : 2000-00-00
> > NOMBATTV :  12.0
> > FIRMWARE : 18.w1 .D USB FW:w1
> > APCMODEL : Back-UPS NS 600
> > END APC  : Mon Oct 16 12:59:51 MDT 2006
> >
> >
> > I'm reasonably certain a serial signal-only connection can't convey
> > that much information to the host (I've no great emotional stake in
> > this, and won't complain if somebody can post similar output from a
> > signal-only UPS).
> >
> > >
> > >  I am using the CentOS 4 based k12ltsp.
> >
> > RPMs are available for RHEL3 at the apcupsd site
> > (
> http://sourceforge.net/project/showfiles.php?group_id=54413&package_id=73150
> ).
> > I think that's the closest match to CentOS 4 (being directly descended
> > from RHEL4).
> >
> > Calvin
> >
> > _______________________________________________
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> > https://www.redhat.com/mailman/listinfo/k12osn
> > For more info see <http://www.k12os.org>
> --
> James P. Kinney III
> CEO & Director of Engineering
> Local Net Solutions,LLC
> 770-493-8244
> http://www.localnetsolutions.com
>
> GPG ID: 829C6CA7 James P. Kinney III (M.S. Physics)
> <jkinney at localnetsolutions.com>
> Fingerprint = 3C9E 6366 54FC A3FE BA4D 0659 6190 ADC3 829C 6CA7
>
>
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>
>
>

-- 
Robert Arkiletian
Eric Hamber Secondary, Vancouver, Canada
Fl_TeacherTool http://www3.telus.net/public/robark/Fl_TeacherTool/
C++ GUI tutorial http://www3.telus.net/public/robark/
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