Hi there, On Sat, 9 Aug 2025, Christian V?lker wrote:
I noticed ... high CPU usage 20% ... throwing away "old" filesystem cache blocks to cache ... directory ... 400GB ... blocks are read only once ... thrown away a couple of hours later ... ... ... "RsyncClientPath" ... to "/usr/bin/nocache /usr/bin/rsync". Now the blocks read during backup are not going into the cache ... So what do you think? Is this a good solution? Or are there any pitfalls?
Does using 20% CPU for a couple of hours actually matter? Presumably by doing this you'll be defeating _all_ caching of anything you're backing up, not just caching of the 400GB directory. That will include directory contents as well as file contents, and may possibly be particularly relevant to incremental backups. You're obviously well in tune with your systems so I guess you'll probably notice any untoward effects. I'd expect significantly increased disc activity because of directory reads which are no longer cached. That might be more relevant for the life expectancy of spinning rust than for SSDs. It might mean that the backups take significantly longer. I'm sure we'll all be interested in your reports, if you find such effects. In a case like this as the data you're backing up is relatively static I think I'd be tempted to put the 400GB directory in a share all of its own, and back it up on a different schedule. But the 'nocache' utility was created expressly for your use case so I don't think it's likely that there will be any serious downsides unless there's some terrible flaw in the implementation which I guess can't be ruled out. I'd be reluctant to do this to my backups for that reason. FWIW where I have for example large database directories - of course not necessarily static data - I don't let BackupPC anywhere near them. Instead I use the DB facilities to create data dumps at intervals (via cron), and then back up the data dumps using rsync (again via cron). -- 73, Ged. _______________________________________________ BackupPC-users mailing list BackupPC-users@lists.sourceforge.net List: https://lists.sourceforge.net/lists/listinfo/backuppc-users Wiki: https://github.com/backuppc/backuppc/wiki Project: https://backuppc.github.io/backuppc/
