Date: Thu, 12 Aug 2010 14:40:02 -0500 From: Ryan Coleman <ryan.coleman@cwis.biz> To: Al Plant <noc@hdk5.net> Cc: David Brodbeck <gull@gull.us>, freebsd-questions@freebsd.org Subject: Re: UPS question Message-ID: <D04386F5-C6C5-4C4C-BEE3-1F209FB85A49@cwis.biz> In-Reply-To: <4C6434E0.20801@hdk5.net> References: <E1B44814-1433-4FBE-902B-BCC1944FBFCD@cwis.biz> <3135A83C-6FD9-4C3B-958F-11EE85221061@mac.com> <5304A319-0406-4510-B6B2-8FD609239FF9@cwis.biz> <43a2b1b16a03a5c58dfb7beaadd0c535.squirrel@www.gull.us> <3AB9F23A-B56C-4176-83C9-F248161066B9@cwis.biz> <cc009d380d95eaa9fee8328a6bbfe4fe.squirrel@www.gull.us> <4C6434E0.20801@hdk5.net>
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On Aug 12, 2010, at 12:52 PM, Al Plant wrote: > David Brodbeck wrote: >> On Wed, August 11, 2010 1:18 pm, Ryan Coleman wrote: >>> On Aug 11, 2010, at 3:06 PM, David Brodbeck wrote: >>>=20 >>>> On Wed, August 11, 2010 12:25 pm, Ryan Coleman wrote: >>>>> He thinks that at 500W needed it would give me about 12 minutes on = a >>>>> 1400VA. My consideration is, then, give the server 2 minutes on >>>>> battery. >>>>> If full power has not been returned, shut down the server but = leave the >>>>> modem (w/ wireless) and switch running with power for up to 6 = hours. >>>> A bit of advice: If this is an unattended system, give some thought = to >>>> how >>>> you will boot the server back up if the outage is longer than two >>>> minutes >>>> but shorter than six hours. Most UPS installations have *some* = kind of >>>> race condition issue if power comes back after the servers have = begun a >>>> shutdown, but in your case it's an unusually long window. >>> Meaning that my 2-minute window is unusually long? If the UPS can = support >>> the system for 12 minutes, I say give it 20% of the life of the = support >>> because our power outages here are usually spikes that kill my = current web >>> server (but amazingly *not* my file server). In fact, one of those = power >>> fluxes occurred last night. I love storms for the light shows, but = hate >>> them for the toll they take on my servers. >> Nope, 2 minutes is fine, maybe even short depending on how long your >> system takes to shut down. What I'm asking about is this scenario: >> 1. Power goes out. >> 2. Server shuts itself down after 2 minutes. >> 3. Power comes back on before the UPS batteries are exhausted. >> The server never sees a power cycle, so it doesn't boot itself back = up >> until someone physically goes and pushes the button. >> ########## >=20 > I have had these power dips and surges here in Hawaii. I have = installed UPS power from two stationary batters that will run the = servers for 12 hours. We have experienced extensive outages in the past = and this was our only solution. Surges are almost impossible to stop. I = have them jump cross a surge protector. I have recently had several UPS = Desktop backups fail from a surge and then a drop below 70 v. This = caused the UPS to have the charging diodes blow. It was cheaper to = replace the UPS 's than to repair them. >=20 > #3. The motherboard bios can be set to stop a server from self booting = from a power outage. >=20 Yes. The downside comes from when the BIOS is told to turn on the server = at, say, 10pm and the power is still out... it starts the process and = runs out of battery mid-way through the boot before it gets the chance = to load the UPS controller. -- Ryan=
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