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From: gregpf@momenta (Greg Presedo-Floyd)
Newsgroups: comp.sys.novell
Subject: Disk duplexing: 3.0/3.1, Adaptec 1540, external SCSI
Summary: Comments on duplexing disks sought
Keywords: duplexing, SCSI, Novell
Message-ID: <1990Dec21.234852.21220@momenta>
Date: 21 Dec 90 23:48:52 GMT
Distribution: na
Organization: Momenta Corporation
Lines: 49

I have questions on "Disk duplexing".

Please email me directly with any/all comments/opinions you have on
the following topic. I will summarize in a later post.

0) Our server environment:

   We have Adaptec 1540 SCSI boards.  They drive Fujitsu 1 Gig external
   winchesters. 

   Netware 386 3.0 (moving to 3.1) .  Ethernet NE2000 and WD8003 coax and
   10BaseT cards.

1) What is "disk duplexing" ?:

      GOAL: A robust/redundant server

      "Disk duplexing" , as I understand it, allows an entire SCSI chain
      (disk controller, all disk(s) connected to that controller) to be
      continuously and transparently have the same data written to each
      redundant side.

      If something on one side goes bad, operations continue and the OS
      sends a warning message out.

      I think I need to go to an Adaptec re-seller and get a Netware
      "disk duplex" NLM to do this.

2) QUESTIONS about "duplexing" :

      Is my specific hardware "duplex-able" ? 
      Will this work ?  Is it working at your site ? 
      How hard was it for you to set up ?
      Has anyone had a disk/controller failure and had this save them ?
      Anyone know a source for sales and support of this in the SF Bay area ?

      A supplimentary thing that I will do to make our server operations 
      robust is to have an identical second server, also disk duplexed,
      operating and on-line or at least powered down and standing by.

      Will these 2 things make my server as robust as possible ?
      More suggestons ?

Thanks !
-- 
Greg Presedo-Floyd            "Representing myself, only"
Momenta Corporation
295 North Bernardo Ave
Mountian View, CA 94043       uunet: {apple,leadsv,hpdtc}!momenta!gregpf