[Beowulf] Re:UPS system for Linux cluster

[Gerry Creager]

Huw Lynes wrote:
> On Wed, 2009-04-29 at 11:21 -0700, John Bushnell wrote:
> 
>> Another reason for not having UPS power for an entire cluster is 
>> cooling.  In our server room, if we lose regular power, we lose our 
>> large AC units as well.  So we need to be careful what we keep plugged 
>> into our emergency power circuits (a relatively tiny amount of 
>> equipment).  Having an entire stack of nodes churning away during a  
>> power outage would kill us pretty quickly.
> 
> 
> The alternative approach is to UPS everything. Which is what we do.
> Although we only have a short run-time installed which will bridge us to
> the diesel generator.
> 
> In the event that the diesel doesn't kick-in the cluster will cleanly
> shut itself down and wait for the UPS to tell it everything is back to
> normal (or until an admin intervenes, whichever comes first).

I would put a strong agreement on to this comment.  There are 
significant benefits to performing an orderly shutdown, then having your 
nodes not restart on power restoration.  If you don't have a GOOD 
mechanism to keep them up through a power problem, it's worth the peace 
of mind to babysit them during a restart, regardless of how inconvenient 
it is.

gerry
-- 
Gerry Creager -- gerry.creager at tamu.edu
Texas Mesonet -- AATLT, Texas A&M University	
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