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From: jas@rtech.UUCP (Jim Shankland)
Newsgroups: comp.unix.wizards
Subject: Re: Backups on Live Systems
Message-ID: <867@rtech.UUCP>
Date: Sun, 31-May-87 14:01:34 EDT
Article-I.D.: rtech.867
Posted: Sun May 31 14:01:34 1987
Date-Received: Tue, 2-Jun-87 05:35:57 EDT
References: <132@dvm.UUCP> <725@aramis.rutgers.edu> <20070@sun.uucp>
Reply-To: jas@rtech.UUCP (Jim Shankland)
Organization: Relational Technology, Alameda CA
Lines: 20

In article <20070@sun.uucp> shannon@sun.uucp (Bill Shannon) writes:
>I'm curious, does anyone have any really good ideas about how to
>do reliable backups on active filesystems?  Would such backups,
>by necessity, have to be done through the filesystem, rather than
>through the raw device as dump does?

Well, I'll let others judge what's a "really good" idea, but people
who need to backup active databases do "fuzzy dumps."  The idea is to
dump a live dataset, but keep a log of changes made to pages that have
already been dumped, and then apply the log to the dump that was made.

To do this to UNIX would require kernel support.  Whether a system
call to snapshot a cooked device really belongs in the kernel is
open to debate; but it would get the job done.  Anybody have a better
idea?
-- 
Jim Shankland
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