MASAKI Yuhsuke posted on Fri, 21 Aug 2015 02:11:46 +0900 as excerpted: > I want to "soft" mirroring between two remote btrfs volumes. > I tried to use btrfs send/receive [but] it failed everytime. > > 1st ) Pipe with SSH, to fresh filesystem. sender was flozen after > transfared 2.79TiB. > 2nd ) Delete snapshots and try again. sender was flozen after transfared > 1.34TiB. [...] > (Sender) ... Linux 4.1.5-1-MANJARO ... > (Receiver) ... Linux 3.10.0-229.11.1.el7.x86_64 ... On this list current kernels are strongly recommended, as btrfs remains in heavy development and is still not entirely stable yet. Now redhat (and presumably centos) does port many of the btrfs stability patches and some of the functionality back, such that the btrfs above is probably newer than the 3.10 would suggest, but there's still a rather large gap between the 4.1 on the sender side and the 3.10 on the receiver, and a lot of send/receive bugs have been found and fixed in the eleven intervening kernel cycles... about two years worth of development on a filesystem that as I said is under "heavy development"... between the two. In fact, given that the "experimental" labels didn't even come off until 3.12, IIRC, a 3.10 kernel is still officially experimental btrfs where even *more* stress was placed on keeping current as stable-patch backports weren't yet routine and thus should be *WELL* out of service more than two years and eleven kernel cycles later! So I'd suggest trying a relatively new kernel, closer to the 4.1 on the receiver side, on the sender side as well, at least to test if it makes a difference in your send/receive results. If possible, I'd recommend testing with the same kernel version, perhaps the latest longterm-stable series 3.18 (with 3.18.20 now current according to kernel.org), or the latest stable 4.1, on both. You can try syncing up userspace versions as well (4.1.2 being latest stable last I checked a week or so ago). Again, for testing, at least. That way, you eliminate version differences as a possible problem. If it works then, I'd suggest filing a bug with RH/CentOS, since their supposedly stable-backported version isn't compatible with a newer version, and that'd be a bug, due either to lack of appropriate backporting or lack of keeping reasonably current versions with a still in heavy development filesystem, one of the two. If it doesn't work with send/receive versions synced and either current stable 4.1 series or latest current LTS 3.18 series, then it's a more current bug and this is the right place to report it, updated with the synced-current-version test results. Because I know that quite a few send/receive fixes actually did go in over the last couple years, and while your distro may well have backported them, this is the upstream list, not your distro list, and that version number still says to us that you're using a more than two years outdated kernel, where btrfs was in fact still experimental, and for all we know, it's still lacking all those send/receive patches that have been applied in the mean time, and is thus still crawling with bugs that have long been exterminated in current stable. -- 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
