ADSM-L

Re: Archive vs. Backup

1999-01-29 10:10:45
Subject: Re: Archive vs. Backup
From: Richard Sims <rbs AT BU DOT EDU>
Date: Fri, 29 Jan 1999 10:10:45 -0500
>It could actually be much worse than that, as we have discovered.
>The default behavior of Archive is to FOLLOW SYMBOLIC LINKS.

This is as it should be.  The intent of archival operations is to preserve
images of data at given points in time, to serve versioning, legal, and
other needs.  A symbolic link is only an allusion to data and just doesn't
fit the paradigm.  The purpose of Archive is to capture data at any given
instant in time, and that's what it does.  It does not capture symbolic
links or directories (though it remembers the directory structure for
basic reconstruction upon Recall).

Customers are trying to use Archive to make archival "backups" outside of
the Backup function due the the cumbersomeness of Backup retention
rule sets and because it remains exceedingly awkward to select Management
Class even in ADSMv3.  But Archive and Backup have different purposes,
and as we see, customers attempting to use Archive as a backup variant
are finding it less than satisfactory.  That's not a reflection on Archive
so much as in the inflexibilities surrounding Backup, which cause
customers to resort to Archive.  Selective Backup makes more sense, but
still participates in the backup set version limits, which interferes with
retention of the regular backups.

Customers seeking to make backup sets outside of the regular backups need
to do it with a different management class, where you can specify separate
rules and limits.  Long-term, we need IBM to make it possible to more
readily select management class, as on the command line.

      Richard Sims, Boston University OIT
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