Hello, I had a broken hard-disk from which ddrescue recovered all but about 1600MB of data. As a result, the copy of it had roughly 50000 uncorrectable errors as reported after scrub. I have saved the dmesg log recorded during this scrub, parsed logical numbers out of it and finaly used "btrfs inspect-internal logical-resolve" to obtain a list of files. However, after manually removing or restoring those files, the subsequent run of "btrfs scrub" still produced >45000 uncorrectable errors. Indeed, the reported files that were again obtained with the above method, are damaged (input/output error on cat > /dev/null). It was suggested that rate-limiting could be the cause of this. I then recompiled the kernel with the (the, as in 4.9.24 there is only one occurance of it in btrfs_printk) "if (__ratelimit..." conditional commented out, rebooted and disabled dmesg ratelimiting with sysctl kernel.printk_ratelimit=0. Then again ran scrub. The result of this scrub was 41000 uncorrectable errors. However, after manually repairing all the problems and re-running scrub, 39000 uncorrectable errors still remain. Is there more rate-limiting going on? If so, how do I disable it? It was also suggested to me to run btrfs check --check-data-csum, but it seems exceptionally slow (roughly 4 MB/s). Has this been addressed or am I doing something wrong? kernel 4.9.24 btrfs-progs v4.6.1 With kind regards, Fedja
