On Sat, Oct 26, 2019 at 07:43:29AM +1100, Dave Chinner wrote: > NFSv2 had a maximum client IO size of 8kB and writes were > synchronous. The Irix NFS server had some magic in it (enabled by > the filesystem wsync mount option) that allowed clients to have two > sequential 8k writes in flight at once, allowing XFS to optimise for > 16KB write IOs instead of the normal default of 64kB. This > optimisation was the reason that, at the time (early-mid 90s), SGI > machines had double the NFS write throughput of any other Unix > systems. > > I'm surprised we still support NFSv2 at all in this day and age - I > suspect we should just kill NFSv2 altogether. We need to keep the > wsync option around for HA systems serving files to NFS and CIFS > clients, but the 8kB IO size optimisations can certainly die.... Last time I talked to the NFS folks there still were some very obscure v2 use cases left (embedded devices that can't be upgraded). But yeah, I'll add a patch to stop overriding rsize/wsize with the sync option.
