[Nut-upsdev] External Devices

[Philip Ward]

Thanks for your replies. When first attempting to configure nut I considered 
using the current master/slave plus MINSUPPLIES to accomplish the task, but 
it is ever so slightly inadequate.

Imagine 4 UPSs. Two powering a server and two powering a disk array. You would 
set MINSUPPLIES to 2 since each device requires at least one UPS. However, 
there is no logic that says "only shutdown if the two UPSs that have failed 
are both powering the same device". If 2 UPSs fail then it could be one each, 
or it could be that both UPSs powering the disk array have failed.
My changes enable you to say that the server needs a minimum of 1 supply and 
that the disk needs a minimum of 1 supply.

I'll get patches sorted out and post them to the list. If they get accepted 
here then I'll send the necessary changes to the WinNut maintainers.

Phil.

On Thursday 30 November 2006 01:29, you wrote:
> > I'm new to the list, and would like to make a contribution to nut.
>
> Contributions are always welcome.
>
> > Nut does a superb job of monitoring the UPS(s) that power servers, but
> > your server may want to monitor other UPSs as well.
>
> This configuration is mentioned in the reference configurations in the
> documentation. Or at least, used to be mentioned (I can't check this right
> now).
>
> > You may have a SAN attached
> > disk array and want to monitor its UPS(s) in order to shutdown yourself
> > before the disk dies and you lose data. There may be other devices as
> > well that would cause you to want to shutdown before they lose power. To
> > this end I have added the EXTMON and EXTMINSUPPLIES directives to nut.
> >
> > EXTMON <devicename> <ups> <power> <username> <password>
> > EXTMINSUPPLIES <devicename> <value>
> >
> > This allows you to say which UPSs supply my disk array and how many
> > supplies it needs.
>
> Like Charles already mentioned, where is this different from specifying
> MINSUPPLIES and the proper slaves for NUT like we have now?
>
> Regards, Arjen

-- 
Philip Ward.
Unix Systems Administrator.
Ext 7274.

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