Reporting as per the instructions in the BtrFS wiki. I have a BtrFS RAID1 file system on two 8TB spindle drives. Was created fresh on Ubuntu 18.04.2 with the 4.18 kernel, May 2019. Lives its life mounted with compress-force=zstd. No problems with weekly scrubs across upgrades: * 18.04.2, kernel 4.18 * 18.04.3, kernel 5.0 * 18.04.4, kernel 5.3 Upgraded to Ubuntu 20.04 LTS with the 5.4 kernel in May 2020, and saw lots (50 instances in syslog) of errors in the next weekly scrub: May 17 22:31:26 server kernel: [456527.977063] BTRFS critical (device sdd): corrupt leaf: block=1552203186176 slot=82 extent bytenr=135271284736 len=4177879734039097329 invalid extent data ref hash, item has 0x39facf7b95b42ff0 key has 0x39facf7b95b42ff1 May 17 22:31:26 server kernel: [456527.977483] BTRFS error (device sdd): block=1552203186176 read time tree block corruption detected Eventually causing the scrub to fail with status "aborted" about one quarter of the way through its normal run time. Rebooting back into the 5.3 kernel (uname says 5.3.0-46-generic) allows a scrub to run completely and exit 0, no errors found or reported. File system appears to be working fine under this kernel. I'll attempt to try some later kernels provided by Canonical's "mainline kernel" project. I have debs for 5.6.13 which I'll install and test when I can get some downtime in the next week. If there's any other information that can help, please let me know. -Dan
