-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Stefan Kaltenbrunner wrote: > Joshua D. Drake wrote: >> Stefan Kaltenbrunner wrote: >>> how is that making it different in practise ? - if both are on the same >>> UPS they are affectively on the same power bus ... >> Well I was thinking the bus that is in the wall. I would assume that >> people were smart enough to have independent UPS systems for each server. >> >> city power->line conditioning generator->panel->plug->UPS->server >> >> wash, rinse repeat. > > the typical datacenter version of this is actually more like: > > city power->UPS (with generator in parallel)->panel->plug Right, this is what we have at our colo except that I add a UPS where appropriate in between panel and plug. > city power->flywheel->(maybe UPS)->panel->plug > > it is not really that common to have say two different UPS feeds in your > rack (at least not for normal housing or the average corporate > datacenter) - mostly you get two feeds from different power distribution > panels (so different breakers) but that's about it. > Having a local UPS attached is usually not really that helpful either > because those have limited capacity need space and are an additional > thing that can (and will) fail. We don't have the capacity issue. We use the UPS explicitly for specific cases (like the one mentioned at the beginning of the thread). The whole idea is to insure clean shutdown in case of "total" power failure. Sincerely, Joshua D. Drake > > > Stefan > - -- === The PostgreSQL Company: Command Prompt, Inc. === Sales/Support: +1.503.667.4564 24x7/Emergency: +1.800.492.2240 PostgreSQL solutions since 1997 http://www.commandprompt.com/ UNIQUE NOT NULL Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate PostgreSQL Replication: http://www.commandprompt.com/products/ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFG4xM5ATb/zqfZUUQRAszhAJ4qmwJQFHd/O5/alOSg1exrYEDe0wCeN6na 8BgWWO1aGELPOuX3xivEBVU= =ETwV -----END PGP SIGNATURE----- ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@xxxxxxxxxxxxxx so that your message can get through to the mailing list cleanly