On Tue, Jul 17, 2018 at 4:47 PM, Tomas Vondra <tomas.von...@2ndquadrant.com> wrote: > Makes sense, I guess. But I think many claims made in this thread are > mostly just assumptions at this point, based on our beliefs how CoW or > non-CoW filesystems work. The results from ZFS (showing positive impact) > are an exception, but that's about it. I'm sure those claims are based > on real-world experience and are likely true, but it'd be good to have > data from a wider range of filesystems / configurations etc. so that we > can give better recommendations to users, for example.
I agree that there's a lot of assuming going on. > That's something I can help with, assuming we agree on what tests we > want to do. I'd say the usual batter of write-only pgbench tests with > different scales (fits into s_b, fits into RAM, larger then RAM) on > common Linux filesystems (ext4, xfs, btrfs) and zfsonlinux, and > different types of storage would be enough. I don't have any freebsd box > available, unfortunately. Those sound like reasonable tests. I also don't think we need to have perfect recommendations. Some general guidance is good enough for a start and we can refine it as we know more. IMHO, anyway. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
