On 17/10/2016 22:50, Karl Denninger wrote:
I will make some effort on the sandbox machine to see if I can come up with a way to replicate this. I do have plenty of spare larger drives laying around that used to be in service and were obsolesced due to capacity -- but what I don't know if whether the system will misbehave if the source is all spinning rust. In other words: 1. Root filesystem is mirrored spinning rust (production is mirrored SSDs) 2. Backup is mirrored spinning rust (of approx the same size) 3. Set up auto-snapshot exactly as the production system has now (which the sandbox is NOT since I don't care about incremental recovery on that machine; it's a sandbox!) 4. Run a bunch of build-somethings (e.g. buildworlds, cross-build for the Pi2s I have here, etc) to generate a LOT of filesystem entropy across lots of snapshots. 5. Back that up. 6. Export the backup pool. 7. Re-import it and "zfs destroy -r" the backup filesystem. That is what got me in a reboot loop after the *first* panic; I was simply going to destroy the backup filesystem and re-run the backup, but as soon as I issued that zfs destroy the machine panic'd and as soon as I re-attached it after a reboot it panic'd again. Repeat until I set trim=0. But... if I CAN replicate it that still shouldn't be happening, and the system should *certainly* survive attempting to TRIM on a vdev that doesn't support TRIMs, even if the removal is for a large amount of space and/or files on the target, without blowing up. BTW I bet it isn't that rare -- if you're taking timed snapshots on an active filesystem (with lots of entropy) and then make the mistake of trying to remove those snapshots (as is the case with a zfs destroy -r or a zfs recv of an incremental copy that attempts to sync against a source) on a pool that has been imported before the system realizes that TRIM is unavailable on those vdevs. Noting this: Yes need to find some time to have a look at it, but given how rare this is and with TRIM being re-implemented upstream in a totally different manor I'm reticent to spend any real time on it. What's in-process in this regard, if you happen to have a reference?
Looks like it may be still in review: https://reviews.csiden.org/r/263/ _______________________________________________ freebsd-stable@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"