Re: [bu-users] Possible to backup to another machine?

[<al...@ge...>]

 > Vincent Stemen writes:
 > > al...@ge... wrote:
 > >
 > > Hello all.
 > > Right now I don't have a disk that I can mount on my machine.  I have
 > > access through ssh/scp to another machine with large backup disks, but
 > > the computer manager does not want that they be mounted on my
 > > computer.  Is it possible to use bu to backup to that machine?  I'm
 > > afraid it's not, but in this case would it be possible to extend bu so
 > > it could do it?  If so, would it be very difficult or extremely
 > > difficult :-)
 > >
 > > Regards,
 > > Alain
 >
 > Off the top of my head, I suspect it would be possible by streaming the
 > files to something like rsync rather than pax.  It would take some
 > research and experimentation.
 >
 > I am sure it could be done using a separate call to [rs]cp for each file
 > but I moved away from doing that with bu because incremental backups are
 > up to 7 times faster by directly statting the dates and streaming the
 > names of the newer files to a single pax process.  That was with direct
 > file access from a mounted nfs/local FS.  With rcp, for incremental
 > backups, it would be even slower because it would have to do a separate
 > remote execution of the shell stat command to get the file date for each
 > file as well.  Of course the stat issue would be the same with rsync
 > unless I ran rsync in update mode and let it take care of choosing what
 > has changed.  Of course this takes some of the control away from bu.
 > It would take some thought and tests to determine if I could retain all
 > of bu's features like detailed logging, etc.  I should still be able to
 > use the bu Exclude patterns because rsync does have the ability to pass
 > exclude patterns to it.
 >
 > I am not sure it is something I will likely have time to look into
 > extensively very soon.  I still have some other features I have been
 > promising for bu for some time, that I need to implement first.
 > However, my priorities could change because it would be a nice feature
 > for backing up to a remote machine over the Internet.  Something we have
 > begun to need from time to time ourselves.
 >
 > If anybody has any ideas for other methods of implementation I am open
 > to hearing them.
 >
 > I am not sure how rsync does it without a special daemon on the remote
 > end.  If the rsh/ssh API libraries provide the ability stat, and copy
 > multiple files while holding the same connection open, it would be worth
 > looking into.  I did find there is a perl rsync module as well as a perl
 > ssh module that would need to be researched.  Or there may be the option
 > of writing something in C.
 >
 > Currently, for example, the way I keep our remote web server backed up
 > to our local machines is by running bu on the webhost to a local backup
 > directory.  Then I periodically run rsync on our local machine to backup
 > new files in the remote webhost:/backup directory to the local machine
 > using a script with a command something like this:
 >
 >     rsync --rsh=ssh -auv root@webhost:/backup/ /backups/webhost
 >
 >
 > If your computer manager refuses to allow NFS because of security
 > concerns, you might want to suggest they look into AFS.
 >
 >     http://en.wikipedia.org/wiki/Andrew_file_system
 >     http://www.openafs.org/
 >
 > Of course, it would not surprise me if their concern is stability if they
 > are running Linux.  Linux has had NFS stability issues for years.  It
 > was _one_ of the main issues that forced us over to BSD a long time ago,
 > after not being able to complete backups for months because our Linux
 > file server crashed every time, with heavy NFS access.  After years,
 > they still have not fixed the bugs.  We are using a modern Linux based
 > TV server for our DVR (because we do not have BSD drivers for the
 > Hauppauge mpeg encoder cards).  When copying a large mpeg file to/from
 > a fast machine to a slower machine the Linux box still hangs.  So we
 > just use it as a dedicated box for streaming the data to our BSD
 > machines, and use them for the video file servers.
 >
 > - Vincent

Thank you very much, Vincent, for the very detailed answer.  It's way
enough to convince me I should probably not try to do it myself, at least
before trying harder on my computer manager, or perhaps buy a disk.

Alain

PS: I have not received my initial email through the list (that is,
the one to which you answered, starting with "Hello all. Right now...").  I
wonder if this is normal (but I remember I used to receive those
emails in the past), although I do receive the emails from the other
list's members) or if this could be related to the management list's
problems we discussed in private.