From owner-freebsd-hackers Thu Mar 5 23:39:34 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id XAA02063 for freebsd-hackers-outgoing; Thu, 5 Mar 1998 23:39:34 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from zwei.siemens.at (zwei.siemens.at [193.81.246.12]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id XAA01805 for ; Thu, 5 Mar 1998 23:38:37 -0800 (PST) (envelope-from lada@ws2301.gud.siemens.at) Received: from ws2301.gud.siemens.co.at (root@firix [10.1.143.100]) by zwei.siemens.at with ESMTP id IAA07108; Fri, 6 Mar 1998 08:31:36 +0100 (MET) Received: from ws6423.gud.siemens.at (ws6423-f.gud.siemens.co.at) by ws2301.gud.siemens.co.at with ESMTP (1.40.112.8/16.2) id AA178539371; Fri, 6 Mar 1998 08:29:31 +0100 Received: by ws6423.gud.siemens.at (SMI-8.6/SMI-SVR4) id IAA29905; Fri, 6 Mar 1998 08:29:58 +0100 Date: Fri, 6 Mar 1998 08:29:58 +0100 From: lada@ws2301.gud.siemens.at (marino.ladavac@siemens.at) Message-Id: <199803060729.IAA29905@ws6423.gud.siemens.at> To: dmlb@ragnet.demon.co.uk, shimon@simon-shapiro.org Subject: Re: SCSI Bus redundancy... Cc: wilko@yedi.iaf.nl, julian@whistle.com, hackers@FreeBSD.ORG Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Md5: zprwN2/EZSNXNTAwKidoRQ== Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > 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 > To: Duncan Barclay > Subject: Re: SCSI Bus redundancy... > Cc: Wilko Bulte , 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