ADSM-L

Re: "saving" tapes (or management's ideas...)

1999-01-26 01:59:42
Subject: Re: "saving" tapes (or management's ideas...)
From: Zvi Bar-Deroma <zvika AT AESERV.TECHNION.AC DOT IL>
Date: Tue, 26 Jan 1999 08:59:42 +0200
Dwight,

Thanks for your analysis. The problem however, is that I cannot know beforehand
which files would be doomed for non-backup, and these files are scattered
all over the users' filesystems. It is perfectly possible (and this is the
way it probably will be) that in a directory some files will be still in the
normal backup, and others (old ones) to be non-backed up, so wildcarding and
doamins are of little (if any) help. In addition, what would happen once a file
from the "non-backup" is changed and should be backed up ?

Regards,
/Zvika

On Mon, 25 Jan 1999 decook AT amoco DOT com wrote:

>      *** numerous include/exclude statements...
>         each file on the client is run through (bottom to top) the
>      include/exclude list until a match is found.  If your hit rate of a
>      client file in your include exclude list made a nice bell curve around
>      the median entry (which it probably won't since these lists tend to
>      EXCLUDE files and any comparisons that purculate out the top are
>      included by default) you would have say :
>      10 million client files
>      10 thousand excludes
>      nice 50% average hit rate
>      yields 50,000,000,000 (50 billion comparisons)
>      BUT like I said, mainly excludes with default includes if no match
>      found so I'd use 90% for the average excludes compared prior to a
>      decision being made so we would have 90 billion comparisons.
>      OK, how fast is your CPU ? ? ?
>      Still boils down to 0 is way less than 50 billion which is less than
>      90 billion.
>
>      That's why there is the "DOMAIN" statements... domains are file
>      systems / volumes / (platform specific whatever) and if the fs/vol/xxx
>      isn't in the domain, the files within never make it to the
>      include/exclude's.  100 files compared in an incl/excl of 101 with the
>      top entry being a wildcarded entry to catch all 100 of your compared
>      files will still yield 10,000 comparisons just to back up ZERO of the
>      files... if the files were all on a single volume and that volume
>      wasn't listed in the domain statement... 1 compare would exclude all
>      of them (more or less... they wouldn't even be built into the list to
>      run through the inclexcl)
>
>      this still leaves you with a ton of manual work to seperate & isolate
>      data on your client servers...
>
>      look at it as job security !
>
>      Hope the adsm info is a little help
>      later,
>            Dwight
>
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