excessive resync errors from 4.2 restore

[Henry Spencer]

>   Our monthly dumps of the user filesystem on an Eagle (~350 Mb) are
> running into 8 or 9 tapes.  Recently, we've been trying to restore(8)
> individual files from these dumps.  We are getting lots of 'resynch'
> error messages and are unable to restore several files.

Do you run your dumps while the system is active multi-user?  My
understanding is that 4.2 dump is better about this than the old Unix
dump, but it's probably less than perfect.  It is extremely hard to
build a dump program that will run perfectly when the file system
is changing underfoot, and I don't believe Berkeley tried.  Truly
reliable dumps require a quiescent file system, which in practice
means you'd better unmount it to make sure it's really idle.  This
generally means that you have to run your dumps single-user.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry