Gian-Carlo Pascutto posted on Mon, 13 Apr 2015 16:06:39 +0200 as excerpted: >> Defrag should force the rewrite of entire files and take care of this, >> but obviously it's not returning to "clean" state. I forgot what the >> default minimum file size is if -t isn't set, maybe 128 MiB? But a -t1 >> will force it to defrag even small files, and I recall at least one >> thread here where the poster said it made all the difference for him, >> so try that. And the -f should force a filesystem sync afterward, so >> you know the numbers from any report you run afterward match the final >> state. > > Reading the corresponding manual, the -t explanation says that "any > extent bigger than this size will be considered already defragged". So I > guess setting -t1 might've fixed the problem too...but after checking > the source, I'm not so sure. Oops! You are correct. There was an on-list discussion of that before that I had forgotten. The "make sure everything gets defragged" magic setting is -t 1G or higher, *not* the -t 1 I was trying to tell you previously (which will end up skipping everything, instead of defragging everything). Thanks for spotting the inconsistency and calling me on it! =:^) -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
