uucping whole trees?

[John Chambers]

Well, here I am again, with another "Has anyone done this yet?" question.
This time the problem is:  Do there exist Unix tools for copying a whole
heirarchy of files intact from one system to another?

Before you say "RTFM", I'll go into the obvious approaches and explain
some of the gotchas in all of them.

First, the trivially obvious one:
	find /usr -exec uucp {} somewhere!/usr/joe \;
This does several things wrong.  First, uucp will flatten it out into
a single directory.  There are ways to get around this, but then you
run into the real killer:  information about links is lost.  You end
up with multiple copies of a file, rather than multiple links to the
same file.

OK, so we go to cpio (or tar, if you prefer).  We try:
	find /usr -print |cpio -o >foo.cpio
	uucp foo.cpio somewhere!/usr/joe/foo.cpio
	...
	cpio -ivdum foo.cpio
This has several problems.  First, it requires enough free disk space to
hold too.cpio, and in /usr case, that means that you'd better have half
your disk free.  The receiver has the same problem.  

Second, uucp package will almost certainly fail to transfer foo.cpio in
most cases.  The /usr/spool/uucp directory is very often in a separate
disk partition (for good reason); uucp will try to first copy foo.c into 
a temp file /usr/spool/uucp/TM.12345.6789, and there won't be space.  If
it should perchance succeed in getting the file across, it will then try
to mv it to /usr/joe/foo.cpio, and if this is in a different file system,
the sender will time out and report the transfer has failed.  [In this
case, it might actually get there, but uucp will try it again in another
hour, causing much congestion.]

The obvious thing to do next is to break the list up into a bunch of lists,
and send over a flock of little cpio archives.  This is easier said than
done.  You have to somehow find out what files are multiply linked, and
arrange to have them included in the same archive, or you lose the links.

I'm contemplating writing some programs to do this.  I figure it'll take
a day or two.  But I thought maybe I'd first ask around and see if anyone
has already solved it.  If there is a program to do it, and it takes me
less than a day to get it running, I'll save some time.  If I can't find
a solution, I guess I'll just write my own, and maybe post it.

It seems that others must have faced this problem before.  The 'cptree'
script works just fine on a single machine; I basically need something
that will do the same across a uucp (or other file-transfer) link.

-- 
	John M Chambers			Phone: 617/364-2000x7304
Email: ...{adelie,bu-cs,harvax,inmet,mcsbos,mit-eddie,mot[bos]}!cdx39!{jc,news,root,usenet,uucp}
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