Online UPS systems kick ass
For almost a year and a half I’ve had one server, a Dell PowerEdge 800, randomly reboot itself with no warning in its syslog. The problem component is a CERC 6 channel SATA RAID card (from Dell) that is extremely sensitive to power supply fluctuations.
Even though it was connected to an APC UPS re-configured from its default to its most sensitive settings the server would end up rebooting, usually right after transferring on or off the UPS battery. This happened a lot due to the insane, and widely varying, load levels the rest of the (manufacturing) machinery in the building consumes.
Simply put, a server rebooting itself, especially without any notice, is unacceptable. I could not trust the machine. Just after this started happening, I put a scope on the machines input power and could see just how bad the power was. I also noted that I often only got email for the UPS battery kicking in, but never out since the machine would reboot before the monitoring software registered the status change and submitted the mail. So, knowing that there was nothing I could realistically do about the bad power situation, I said we should buy an online (double conversion) UPS. About 14 months later I finally got one. It kicks ass.
I installed the unit on Tuesday just before a mild thunderstorm that night and a really big one late Wednesday afternoon and evening. After an unknown amount of brownouts (the UPS will actually use input voltages between 65 and 138V to constantly charge its battery) and 9 complete blackouts (18 transfers, well really just losses of input power since output power is *always* off of the battery) the server was still going. This was a first, this server had never made it through a single thunderstorm without rebooting. Fantastic. If it keeps it up for three months or so, maybe I’ll start to trust it.
Of course, I probably should have thrown the server back at Dell in the first place since NONE of our other servers, workstations, or digital electronics on various machines have any problems as bad as this one server. If it wouldn’t be such a pain to transfer the load to another machine I probably would have. Oh well, at least that server and everything else I plugged into the online backup (a couple of switches, a Cisco router and Nortel Voicemail) should last a lot longer having nice clean power to live on.
Anyway, the online backup I got was a Tripp Lite SU1500RTXL2Ua. $799 US on their website. You should be able to get it for less than $900 in Canada… wholesale cost before shipping (it’s heavy) is about $750 CDN.
3 comments July 30th, 2006
