Hi, Timothy J. Massey wrote on 24.01.2007 at 23:21:28 (04. Woche) [Re: [BackupPC-users] Avoiding long backup times]: > [EMAIL PROTECTED] wrote on 01/24/2007 > 09:28:51 PM: > > > I like the idea of taking *any* identical file from the pool as reference > > though. I don't know if it is possible (i.e. whether the remote rsync > > will transfer one checksum covering the whole file before the local part > > needs to commit to selecting one file), but it certainly would be a > > worthwhile speedup. > > This could be a most valuable speedup for the initial backup of remote > hosts.
that was what I was thinking. I have, in the mean time, read Craig's description of rsync operation in the online documentation under "Rsync checksum caching" though (I should have read that a long time ago). Apparently, BackupPC sends block checksums to the rsync on the client and gets back information on which blocks to update and how. That means, a file would have to be selected beforehand. I have no idea if that would be reversible (eg. by not starting the remote rsync as --server) or if it solely depends on the direction the file is transfered (quite likely, as the receiving end cannot tell the sending end what changes to the file it would like to make ... it could request specific blocks though). Probably, if it was possible, BackupPC would already do it. How are multiple --compare-dest options implemented in native rsync, though? > Currently, your choices are to do a painfully slow (or even > impossibly slow) first backup over a WAN link, or physically move the > server to the remote location for the first full backup. This is > usually difficult, and often prevents the other backups the server has > to do from working as well. Or to add directories to the backup set in chunks that can be handled with the available bandwidth, such as by initially having a long BackupFilesExclude list and removing entries one by one. I have some thoughts on transfering a host from one server to another, but I'll have to get back to that later. Regards, Holger ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/backuppc-users http://backuppc.sourceforge.net/
