I've got a btrfs file system set up on 6 drbd disks running on 2Tb spinning disks. The server is moderately loaded with various regular tasks that use a fair bit of disk IO, but I've scheduled my weekly btrfs scrub for the best quiet time in the week. The command that is run is: /usr/local/bin/btrfs scrub start -Bd -c idle /data Which is my best attempt to try and get it to have a low impact on user operations But iotop shows me: 1765 be/4 root 14.84 M/s 0.00 B/s 0.00 % 96.65 % btrfs scrub start -Bd -c idle /data 1767 be/4 root 14.70 M/s 0.00 B/s 0.00 % 95.35 % btrfs scrub start -Bd -c idle /data 1768 be/4 root 13.47 M/s 0.00 B/s 0.00 % 92.59 % btrfs scrub start -Bd -c idle /data 1764 be/4 root 12.61 M/s 0.00 B/s 0.00 % 88.77 % btrfs scrub start -Bd -c idle /data 1766 be/4 root 11.24 M/s 0.00 B/s 0.00 % 85.18 % btrfs scrub start -Bd -c idle /data 1763 be/4 root 7.79 M/s 0.00 B/s 0.00 % 63.30 % btrfs scrub start -Bd -c idle /data 28858 be/4 root 0.00 B/s 810.50 B/s 0.00 % 61.32 % [kworker/u16:25] Which doesn't look like an idle priority to me. And the system sure feels like a system with a lot of heavy io going on. Is there something I'm doing wrong? System details: # uname -a Linux emile 4.4.3-040403-generic #201602251634 SMP Thu Feb 25 21:36:25 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux # /usr/local/bin/btrfs --version btrfs-progs v4.4.1 I'm waiting on the ppa version of 4.5.1 before upgrading, that is my usual kernel update strategy. # cat /etc/lsb-release DISTRIB_ID=Ubuntu DISTRIB_RELEASE=14.04 DISTRIB_CODENAME=trusty DISTRIB_DESCRIPTION="Ubuntu 14.04.4 LTS" Any other details that people would like to see that are relevant to this question? -- Gareth Pye - blog.cerberos.id.au Level 2 MTG Judge, Melbourne, Australia -- 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
