>>> I've one system where a single kworker process is using 100% >>> CPU sometimes a second process comes up with 100% CPU >>> [btrfs-transacti]. [ ... ]
>> [ ... ]1413 Snapshots. I'm deleting 50 of them every night. But >> btrfs-cleaner process isn't running / consuming CPU currently. Reminder that: https://btrfs.wiki.kernel.org/index.php/Gotchas#Having_many_subvolumes_can_be_very_slow "The cost of several operations, including currently balance, device delete and fs resize, is proportional to the number of subvolumes, including snapshots, and (slightly super-linearly) the number of extents in the subvolumes." >> [ ... ] btrfs is mounted with compress-force=zlib > Could be similar issue as what I had recently, with the RAID5 and > 256kb chunk size. please provide more information about your RAID > setup. It is similar, but updating in-place compressed files can create this situation even without RAID5 RMW: https://btrfs.wiki.kernel.org/index.php/Gotchas#Fragmentation "Files with a lot of random writes can become heavily fragmented (10000+ extents) causing thrashing on HDDs and excessive multi-second spikes of CPU load on systems with an SSD or large amount a RAM. ... Symptoms include btrfs-transacti and btrfs-endio-wri taking up a lot of CPU time (in spikes, possibly triggered by syncs)." -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
