On Sat, Jun 3, 2017 at 2:59 PM, Colin Percival <cperc...@tarsnap.com> wrote:
> On January 24, 1998, in what was later renumbered to SVN r32724, dyson@ > wrote: > > Add better support for larger I/O clusters, including larger physical > > I/O. The support is not mature yet, and some of the underlying > implementation > > needs help. However, support does exist for IDE devices now. > > and increased MAXPHYS from 64 kB to 128 kB. Is it time to increase it > again, > or do we need to wait at least two decades between changes? > > This is hurting performance on some systems; in particular, EC2 "io1" disks > are optimized for 256 kB I/Os, EC2 "st1" (throughput optimized spinning > rust) > disks are optimized for 1 MB I/Os, and Amazon's NFS service (EFS) > recommends > using a maximum I/O size of 1 MB (and despite NFS not being *physical* I/O > it > seems to still be limited by MAXPHYS). > MAXPHYS is the largest I/O transaction you can push through the system. It doesn't matter that the I/O is physical or not. The name is a relic from a time that NFS didn't exist. Warner _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"