On Fri, 28 Jul 2017 17:40:50 +0100 (BST) "Konstantin V. Gavrilenko" <k.gavrilenko@xxxxxxxxxx> wrote: > Hello list, > > I am stuck with a problem of btrfs slow performance when using compression. > > when the compress-force=lzo mount flag is enabled, the performance drops to 30-40 mb/s and one of the btrfs processes utilises 100% cpu time. > mount options: btrfs relatime,discard,autodefrag,compress=lzo,compress-force,space_cache=v2,commit=10 It does not work like that, you need to set compress-force=lzo (and remove compress=). With your setup I believe you currently use compress-force[=zlib](default), overriding compress=lzo, since it's later in the options order. Secondly, > autodefrag This sure sounded like a good thing to enable? on paper? right?... The moment you see anything remotely weird about btrfs, this is the first thing you have to disable and retest without. Oh wait, the first would be qgroups, this one is second. Finally, what is the reasoning behind "commit=10", and did you check with the default value of 30? -- With respect, Roman -- 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
