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From: tony@tui.marcam.dsir.govt.nz (Tony Cooper)
Newsgroups: comp.unix.aux
Subject: Re: Copying A/UX to another disk
Message-ID: <1991Apr23.010830.5923@am.dsir.govt.nz>
Date: 23 Apr 91 01:08:30 GMT
References: <1991Apr17.173127.15460@jato.jpl.nasa.gov> 
 <1991Apr17.215727.1840@eng.umd.edu> <1991Apr18.135204.11057@jato.jpl.nasa.gov> <1991Apr22.112353.18391@helios.physics.utoronto.ca>
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|> |	find / -print | grep -v /mnt | cpio -pdlm /mnt
|> 
|> Well, "something like" ought to be something more like
|> 
|> 	find / -print | egrep -v '^/mnt$|^/mnt/' | cpio -pdlm /mnt
|> 
Well neither of the two is correct. Neither "copies" A/UX to another disk.
They both change the files in subtle ways. Files on both filesystems are
changed in fact and both filesystems are not identical. The only way to make
a copy is by using dump. Dump to tape then restore to disk. Then only two
files get changed on both filesystems (namely the raw disk special files)
and both filesystems are otherwise identical.

To make the copies as identical as possible using cpio use the arguments
cpio -pudlma. The a means that the copied files get their access times
reset to be the same as the original files, the u doesn't mean anything
when copying to a blank disk but is necessary when copying to an existing
filesystem (it ensures that existing files get overwritten).

Using dump is the standard way on the unix world. Users don't like having
their files altered by sysadmins. (NB only the file dates get altered, not
file contents). And if you alter the last access date of users' files you
can never say to them "Look, you have 10MB of data that you have not
accessed for two years. Shouldn't you archive that onto tape?".

Tony Cooper