On Tue, Nov 14, 2017 at 5:27 AM, Nix <nix@xxxxxxxxxxxxx> wrote: > Every time I rebooted I got warnings that bcache couldn't clean up in time, and I suspect this caused corruption in the end (fairly fast, actually, less than a month after starting using bcache: it had only just finished populating). What did you see? A message like this is normal: [ 2.224767] bcache: bch_journal_replay() journal replay done, 432 keys in 243 entries, seq 40691386 but anything else is strange... If you were consistently seeing other messages that means something unusual was happening (an already badly-corrupted volume or bad hardware). > The thing is in none mode at the moment, waiting for me to revamp my > shutdown process to rotate the initramfs into place at shutdown so I can > unmount the rootfs and stop the bcache, in the hope that that might give > it a chance to shut down neatly. (Even so, finding that dirty shutdown > can corrupt the bcache is unpleasant. I guess nobody does powerfail > tests? How do most people shut down their bcache-on-rootfs systems?) I've been doing a fair amount of powerfail tests with OK results. Unfortunately, my production bcache machines had some unplanned power failure testing in the past week as well. Also I sometimes write crashy kernel code and end up testing unclean shutdown that way. I have not experienced bcache corruption yet, though that doesn't say there's not an issue. This doesn't sound at all like what Alexandr experienced, either. There's not a bucket corruption message in the kernel, -- maybe you saw a bad btree message at bucket xxxxx, block xxx, dev xxxx? What SSD are you using? A known issue is that there are families of SSDs that do not do the right thing on shutdown-- e.g. some devices based around LSI/SandForce that do emergency-writeback-from-RAM that have underprovisioned / missing capacitors. Mike -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
