[Pacemaker] Stonith Device APC AP7900

[Rick Cone]

Devin,

In production I am planning to have 2 separate AP7900 units each plugged
into 2 different APC UPS units to achieve that.  I would then have the
single node name on each, for each of the 2 PS's on the individual systems.
I'm currently testing at our other site that does not have multiple UPS
units, and the splitter was the solution.  I am concerned about 2 node names
on the outlets on the same AP7900, as it failed to work on all the names a
couple of times.  It would get at least 1 (the latter of the 2), put not
always both.  This failure was rare, but did happen.  The solution was to
always have just 1 outlet with the node name on the AP7900.  I have never
seen that fail.  Also, as suggested, I did reduce the interval of the
monitor time from 30s to 2h on the AP7900.  Perhaps that was a factor.

Thanks,

Rick   

-----Original Message-----
From: Devin Reade [mailto:gdr at gno.org] 
Sent: Sunday, November 14, 2010 9:32 PM
To: pacemaker at oss.clusterlabs.org
Subject: Re: [Pacemaker] Stonith Device APC AP7900

Rick Cone <rcone at securepaymentsystems.com> wrote:

> Perhaps I'll just use 1 outlet with the node name,
> with a power splitter to the 2 redundant power supplies to reduce the
> chances of problems.

IMO, if you're going to use a chassis with redundant power supplies,
you're better off with a system that uses an ALOM/DRAC/iLO, or equivalent
that sits between the redundant power bus and the main boards, and
then plug your redundant power supplies into two different circuits.
Otherwise, for what's supposed to be an HA system, you're introducing
unnecessary single points of failure.  I know the arguments about
using an external device for fencing, but in the redundant power case
if you can't reach your ALOM/whatever you're already looking at the
multiple failures.

But it's your datacenter.

FWIW, I can confirm that the AP7900 works just fine and should be 
added to the list of supported devices.

Devin


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