In article ,
Andrew Gabriel wrote:
In article ,
(dmc) writes:
The Dell servers were by far the worst culprits along with the EVA storage.
Sun and HP servers tend to be better. We have dual psu machine feed from
two independant distribution networks and most Dell boxes appeared to
run from one or other psu on not share the load between them. This tended to
cause one side of the rack to be overloaded and cause the breakers to pop :-(

Well, the whole point of splitting the power is so that if one
supply fails, the other continues to run the servers. If either
supply isn't capable of doing that, then there's no point in
splitting the servers across multiple supplies.


Yes, but the start up surge on the dual psu dells was all on one psu. Given we had
plenty of them it meant seriously under speccing the power feeds and hoping they
wouldn't all come up and suck power from the same feed. It was fairly random IIRC
(at least if it was consistant which psu they would pick we could have shared
them about).

Sods law meant that 80% of them would come up on one of the feed tripping it out
are which point they would all switch to the other feed and the surge would trip
that.

As I say, we switched to HP for winblows servers and it got a lot better (maybe
just better psus?) and now we have all the racks sequenced anyway so the problem
has gone for good (he says, touching wood/mdf )

Darren