using tar for incremental backups on 4.2 systems

[dave at uwvax.ARPA]

We have used tar (or a subset of tar actually, it generates tar-tapes)
for incrementals since 4.1 times.  The only problem with the scheme
suggested is the 'find'.  Find is amazingly slow!  I wrote a new find
program which runs through the inode list on the filesystems to be
dumped (gleened from fstab), makes a bitmap of the files to be dumped
and then does a fast transversal of the directory structure for the
names ('sounds like dump' you say?  Yes, that's where I got the idea).
This takes about 10 mins when searching through 1++ gig.  The
differences to tar are that it reads the files it dumps from a file and
can dump to remote tapedrives (only under 4.2).  We also made a
complementary restore program which gives the ability to restore a file
to places other than where they originated.  This all runs very well
(except when the tapedrives die).

Now if I could only get the incremental dump history to work right.....
-- 
Dave Cohrs @ wisconsin
...!{allegra,heurikon,ihnp4,seismo,ucbvax,uwm-evax}!uwvax!dave
dave at wisc-rsch.arpa