What is the difference bertween a coldstart and a warmstart?

[Anonymous user]

We suffered a power loss at one of our data centres over the weekend. Strangely, the logs for the A feed showed a cold start on the power rails, but the B side logs all showed warmstarts. I'm wondering what the difference is, and why the rails would choose to spontaneously warmstart?

Any help greatly appreciated.

Bernie

"B" Feed Log
28.11.2010 08:27:16 Switched Rack PDU: Near overload cleared on bank 1.
28.11.2010 08:16:35 Switched Rack PDU: Near overload on bank 1.
28.11.2010 08:16:33 Switched Rack PDU: Communications established.
28.11.2010 08:16:25 System: Network service started. System IP is (Address) from manually configured settings.
28.11.2010 08:16:25 System: Warmstart.

"A" Feed log
28.11.2010 08:28:21 Switched Rack PDU: Communications established.
28.11.2010 08:28:12 System: Network service started. System IP is (Address) from manually configured settings.
28.11.2010 08:28:12 System: Coldstart

[BillP · Accepted solution]

hi, you can reference [this knowledgebase article|http://nam-en.apc.com/app/answers/detail/a_id/2572/] on the subject.

in summary, a coldstart indicates the power was lost to the network management card and it rebooted where as a warmstart is just a reboot without losing power, much like a PC can be power cycled or "soft rebooted" with a restart command.

what were the switched rack PDUs plugged into? a UPS? ATS? that may help us figure out what happened. do you have any info from the data log at the same time?