Date: Fri, 6 Mar 1998 08:29:58 +0100 From: lada@ws2301.gud.siemens.at (marino.ladavac@siemens.at) To: dmlb@ragnet.demon.co.uk, shimon@simon-shapiro.org Cc: wilko@yedi.iaf.nl, julian@whistle.com, hackers@FreeBSD.ORG Subject: Re: SCSI Bus redundancy... Message-ID: <199803060729.IAA29905@ws6423.gud.siemens.at>
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> From owner-freebsd-hackers@FreeBSD.ORG Thu Mar 5 21:12:11 MET 1998 > X-Priority: 3 (Normal) > Content-Transfer-Encoding: 8bit > Mime-Version: 1.0 > Date: Thu, 05 Mar 1998 12:15:21 -0800 (PST) > From: Simon Shapiro <shimon@simon-shapiro.org> > To: Duncan Barclay <dmlb@ragnet.demon.co.uk> > Subject: Re: SCSI Bus redundancy... > Cc: Wilko Bulte <wilko@yedi.iaf.nl>, julian@whistle.com, hackers@FreeBSD.ORG > X-Loop: FreeBSD.ORG > > > On 05-Mar-98 Duncan Barclay wrote: > ... > > > Are you sure you guys want to use different phases of a the same feed? > > Remember > > all two or three phases come into the building from the same sub-station > > down > > the same pice of cable. Most comman fault is a digger cutting this > > cable taking out all three phases or temp. shorts in the > > overheads to the sub-station (auto reset ater a couple of minutes; > > usually > > from wind blowing the cables together). > > > > You need feeds from seperate sub-stations. > > And then snow levels the cables from the power plant, or a flood destroys > the dam... I recommend 2 separate UPSs for the two inputs. True HA should > be on 48VDC, separate packs, separate feeds. Standard Telco stuff. And then you find yourself in the middle of a nuclear blast... Honestly, don't you think you're overdoing it a bit here. I mean, we're still talking ISP, right? If the power goes, your modems are dead as well. And if you want to UPS that, you're using motor-generator pairs with Diesel backup and don't really care about batteries (a 30 year old Diesel still kicks in within a second and if your power supply cannot stand a few second intermittent failure then you have some seriously underdimensioned power supplies). /Marino > > ---------- > > > Sincerely Yours, > > Simon Shapiro > Shimon@Simon-Shapiro.ORG Voice: 503.799.2313 > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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