ADSM-L

Re: The "incremental forever" paradigm

1998-03-07 15:46:08
Subject: Re: The "incremental forever" paradigm
From: "Kelly J. Lipp" <lipp AT STORSOL DOT COM>
Date: Sat, 7 Mar 1998 13:46:08 -0700
And when was the last time anyone saw the sorts of disasters we're
contemplating in this thread.  We need to worry about this stuff, but not
the exclusion of all else.  Yes, some bad things happen at times, but we're
talking about five bad things in a row here.  Not many of us are that
unlucky.

We don't do full disk restores often.  We have mirroring to save us here.

We don't have a disaster very often.

Two copies of data is enough for anyone.  This means you would have to lose
the original, and both copies before you would have a problem.  And then
you would only have a problem if you actually needed a copy of the three
copies you lost!

ADSM with its data protection features is superior to anything you've ever
done in the past.  Did you worry about this stuff as much in the past?  If
you did and you were satisfied, you probably had your head buried in the
sand.

There were all sorts of assumptions about backups in our previous lives.
 Here are some of them:

If a file existed on a system overnight, it was on an incremental tape and
available for as long as we kept our incremental tapes.

If a file existed on a system over a Saturday night, it was on a full tape
and available as long as we kept our weekly full backups.

If a file existed on a system over a month-end Saturday night, it was on
the monthly full and available as long as we kept our monthly backups.

If a file existed on a system over a year-end Saturday night, it was on the
yearly full and available as long as we kept our yearly backups.

Lots of "ifs" in this scenario.  Lots of data too, which is precisely the
problem: too much data backed up too often.  Sure, if a file existed a long
time we could have many tens of copies of it on tape.  But this isn't a
good thing!  Ask the Pharmaceutical and tobacco industry.  Too much data
for a lawyer to find is bad data.

And the only reason we used the above method in the first place is because
the tools we had only worked that way, or were to cumbersome to use
otherwise.  Using these tools, imagine an incremental forever methodology.
 There was never any possible business requirement that demanded an
incremental every night and a full on the weekends.  The "stupid" tool
demanded this, not our business requirements!

ADSM allows you to define precisely how long to keep information around on
backup tapes.  ADSM allows you to define exactly how many copies of data to
keep.  ADSM allows you backup only that data you would ever have a
requirement to restore. Take the time to decide exactly what your business
needs instead of relying on the power of the tool.  ADSM is powerful enough
to implement any of your business requirements.  It tends to fail miserably
when we ask it to do something that is not a business requirement.
 Something like a weekly full backup for instance.

Pardon the length and fervor of this message, but ADSM is a cool product
and I can't stand to see anyone try to make it act like other less cool
products in the marketplace.

Kelly
What am I doing answering list serve questions on Saturday?