On Fri, Jan 1, 2021 at 11:31 AM Artem Tim <ego.cordatus@xxxxxxxxx> wrote: > > It's faster. Here is some benchmark with different zstd compression ratios https://lkml.org/lkml/2019/1/28/1930. Could be outdated a little bit though. > > But for HDD it makes sense to increase it probably. And IIRC Chris wrote about such plans. There are ideas but it's difficult because the kernel doesn't expose the information we really need to make an automatic determination. sysfs commonly misreports rotational devices as being non-rotational and vice versa. Since this is based on the device self-reporting, it's not great. I use zstd:1 for SSD/NVMe. And zstd:3 (which is the same as not specifying a level) for HDD/USB sticks/eMMC/SD Card. For the more archive style of backup, I use zstd:7. But these can all be mixed and matched, Btrfs doesn't care. You can even mix and match algorithms. Anyway, compress=zstd:1 is a good default. Everyone benefits, and I'm not even sure someone with a very fast NVMe drive will notice a slow down because the compression/decompression is threaded. I expect if we get the "fast" levels (the negative value levels) new to zstd in the kernel, that Btrfs will likely remap its level 1 to one of the negative levels, and keep level 3 set to zstd 3 (the default). So we might actually see it get even faster at the cost of some compression ratio. Given this possibility, I think level 1 is the best choice as a default for Fedora. -- Chris Murphy _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
