On Wed, 27 Feb 2013 at 11:34 -0000, m.roth@5-cent.us wrote:
Is there any way to have rsync compare against a file with a *different* name?
What I'd like to do is compare a vm - whatsit.img against a backup - whatsit.current, that's a symlink to whatsit.timestamp, and if different, *then* make the copy (which my script will then move to whatsit.newtimestamp, and change the symlink to point to the new one, then remove the old (or maybe save an older copy or two).
So: backupdir \ whatsit.20130101 (backup of whatsit.img) whatsit.current -> whatsit.20130101 whatsit.20121201
After script w/ rsync backupdir \ whatsit.20130201 (backup of whatsit.img) whatsit.current -> whatsit.20130201 whatsit.20130101
I'm not quite sure what you are trying to do. A couple of things that I do include:
1) By referencing 'whatsit.current/.' you can be sure to follow a symbolic link on the destination of the rsync. I do this all the time when wanting a different destination directory name.
2) You can use the --link-dest rsync option to create a new tree based upon an older tree. I don't have an example handy but it looks something like:
rsync -aH --link-dest=whatsit-current/. whatsit: whatsit-new
3) Preserve historic backups as hard links (using 'cp'). This leaves 'backup/whatsit' as the current version (slightly inconsistent during the backup operation).
* rsync -aH --delete whatsit: backup/whatsit * monday-saturday: cp -rpl backup historic/daily-YYYYMMDD * sunday: cp -rpl backup historic/weekly-YYYYMMDD * clean up older daily-YYYYMMDD files after 1 month
Some combination of these may help with what you are attempting.
4) I assume you are comparing the contents of the VM disk (as seen by the virtual OS) not the data blocks in the container file itself. rsync is probably not very useful for just the single container disk image file (it might have slight use for vmware disk images composed of many smaller storage segments).
Stuart