Backups

Matthew Gillen me at mattgillen.net
Wed Aug 23 21:30:19 EDT 2006


Chris OConnell wrote:
> Hi Guys,
> 
> I've pretty much switched to Suse entirely, but am unable to figure out
> how to perform a backup.  I assume there must be a CP parameter that
> will say "copy everything in this directory recursively (hidden files
> too) and verify them for size when you are done."
> 
> Does anyone use a script or program they like or would be willing to
> share to backup their files to a removeable drive?

If you must use 'cp', then make sure to use 'cp -a' so that it handles
things like symlinks or device files correctly.  For some *nix foo, learn to
use 'tar'.  As someone else mentioned, rsync can be used to do efficient
updates to an existing backup.

Here's what I do for large directories (if step 1 doesn't take long, then
just use it and don't bother with step 2):
1) use tar for the the initial backup.  Assuming your files are in
/opt/somedir and you want to copy them into /backup/somedir :
 cd /opt ; tar -cvf - somedir | tar -C /backup -xf -

This copies the directory with all the advantages of using tar over cp, but
without creating the intermediate .tar file.

Why do this instead of 'cp'?  Because you can use a slight modification to
backup to remote hosts via ssh:
 cd /opt ; tar -cvf - somedir | ssh -C remotehost tar -C /backup -xf -

Pipes are fun ;-)  Pipes with ssh let you do some really whacky things.

2) for updates, or to verify that the copy is complete, use rsync:
 rsync -avz --delete /opt/somedir /backup/

Note that rsync is picky about the trailing slash on the "source" directory,
and you may or may not want the --delete option (removes files in
/backup/somedir that are no longer in /somedir).   As the man page for rsync
says: be very careful when using --delete about not getting the 'src' and
'dest' mixed up.  When using rsync from the command line, I always double
check the man page to make sure I have the arguments in the right order.

Matt

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