Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!cs.utexas.edu!uunet!portal!cup.portal.com!Fabian
From: Fabian@cup.portal.com (Fabian Fabe Ramirez)
Newsgroups: comp.sys.mac
Subject: Re: Inefficiency with DiskFit 1.5 during backups
Message-ID: <17174@cup.portal.com>
Date: 14 Apr 89 23:45:46 GMT
References: <1122@atux01.UUCP> <23539@coherent.com> <28902@apple.Apple.COM>
Distribution: usa
Organization: The Portal System (TM)
Lines: 26

Greetings,

Here's a reply from Larry Zulch of Dantz Devlopment Corp.

"Optimal use of backup disks must take into account other factros than raw
percentage utilization.  DiskFit employs a rather sophisticated algorithm
that weights quite a number of factors.  In rough order of greater or lesser
weighting, some of these factors include: keeping a file in Finder format, 
utilizing existing space on the backup set, preventing folders from being
fragmented across backup disks, minimizing disk insertions.

If files are removed from the source, DiskFit will remove them from the
backup set and reclaim the space.  It will not, however, move files from one
disk to another in order to release disks from the set--that would be slow
and require a great number of disk insertions or recopying.  Typically, the
amount of data stored on a hard disk ebbs and flows so the released disks 
would have to be added again.  Anyway, relative to data, disks are not
particularly expensive.

We have carefully analyzed the direct and resultant usage of DiskFit 
SmartSet disks and have spent a lot of time tuning the performance.  I do
not think you will find a faster, more reliable way to keep a virtual, or 
shadow, copy of your hard disk for backup purposes.

Larry Zulch
Dantz Development Corp."