Hi, On 12/09/2016 14:59, Michel Bouissou wrote: > [...] > I never had problems with lzo compression, although I suspect that it (in > conjuction with snapshots) adds much fragmentation that may relate to the > extremely bad performance I get over time with mechanical HDs. I had about 30 btrfs filesystems on 2TB drives for a Ceph cluster with compress=lzo and a background process which detected files recently written to and defragmented/recompressed them using zlib when they reached an arbitrary fragmentation level (so the fs was a mix of lzo, zlib and "normal" extents). With our usage pattern, our Ceph cluster is faster with compress=zlib instead of the lzo then zlib mechanism (which tried to make writes faster but was in fact counterproductive) so we made the switch to compress=zlib this winter. On these compress=lzo filesystems, at least 12 where often (up to several times a week) corrupted by defective hardware controllers. I never had any crash related to BTRFS under these conditions (at the time with late 3.19 and 4.1.5 + Gentoo patches kernels). Is there a bug somewhere open with kernel version affected and the kind of usage that could reproduce any lzo specific problem (or any problem made worse by lzo) ? Lionel -- 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
