From owner-freebsd-hackers  Thu Apr  6 19:22:56 1995
Return-Path: hackers-owner
Received: (from majordom@localhost)
          by freefall.cdrom.com (8.6.10/8.6.6) id TAA18809
          for hackers-outgoing; Thu, 6 Apr 1995 19:22:56 -0700
Received: from hq.icb.chel.su (icb-rich-gw.icb.chel.su [193.125.10.34])
          by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id TAA18801
          for <freebsd-hackers@freebsd.org>; Thu, 6 Apr 1995 19:22:32 -0700
Received: from localhost (babkin@localhost) by hq.icb.chel.su (8.6.5/8.6.5) id IAA00249; Fri, 7 Apr 1995 08:21:30 -0500
From: "Serge A. Babkin" <babkin@hq.icb.chel.su>
Message-Id: <199504071321.IAA00249@hq.icb.chel.su>
Subject: Re: large filesystems/multiple disks [RAID]
To: terry@cs.weber.edu (Terry Lambert)
Date: Fri, 7 Apr 1995 08:21:30 -0500 (GMT-0500)
Cc: freebsd-hackers@FreeBSD.org
In-Reply-To: <9504061615.AA12169@cs.weber.edu> from "Terry Lambert" at Apr 6, 95 10:15:50 am
X-Mailer: ELM [version 2.4 PL23]
Content-Type: text
Content-Length: 769       
Sender: hackers-owner@FreeBSD.org
Precedence: bulk

> > How about disk mirroring ? If you have a _mirrored_ database on two 2G
> > disks and then add 2x2G (or may be 1x4G) and get spanned mirrored database. 
> > You get reliability due to mirroring and easy expansion due to spanning.
> 
> That works... but then again, it's an additional support change to
> increase reliability.

> Note that a procedural change could suffice... like adding regular
> backups when there were none before.

Yes. But mirroring gives additional throughput increase for reading
like stripping (and decrease for writing unlike it :-( ). But from
my experience big databases are much more often read than written,
aren't they ?


		Serge Babkin

! (babkin@hq.icb.chel.su)
! Headquarter of Joint Stock Bank "Chelindbank"
! Chelyabinsk, Russia