Re: [bu-users] Possible to backup to another machine?
Status: Beta
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vstemen
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From: <al...@ge...> - 2007-01-15 16:26:04
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> 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. |