Cedric Blancher [cedric.blancher@xxxxxxxxx] wrote: > On 23 April 2014 23:15, Malahal Naineni <malahal@xxxxxxxxxx> wrote: > > Cedric Blancher [cedric.blancher@xxxxxxxxx] wrote: > >> On 23 April 2014 22:44, Malahal Naineni <malahal@xxxxxxxxxx> wrote: > >> > Cedric Blancher [cedric.blancher@xxxxxxxxx] wrote: > >> >> On 23 April 2014 22:24, Malahal Naineni <malahal@xxxxxxxxxx> wrote: > >> >> > Cedric Blancher [cedric.blancher@xxxxxxxxx] wrote: > >> >> >> Are there any options to improve the Linux NFSv4 performance over a > >> >> >> high latency connection? > >> >> >> > >> >> >> We currently use Solaris/Illumos as NFSv4 server and client over a > >> >> >> cross continental Internet connection. Latency is terrible (~220ms) > >> >> >> but the counter this by running work in parallel so the latency is > >> >> >> mostly mitigated. > >> >> >> > >> >> >> We now wish to migrate (short: Away from Oracle because support is > >> >> >> basically unbearable) to Linux (tested SuSE 13.1 and current Fedora) > >> >> >> and build times are 17 times (!!!) SLOWER than on Solaris/Illumos. > >> >> >> > >> >> >> Are there any tunables besides actimeo=300? > >> >> > > >> >> > rsize and wsize may help! You need to figure out if the read is the > >> >> > issue or the write before you dig further. > >> >> > >> >> I already tried to tune rsize/wsize, making them both smaller or the > >> >> maximum of 1048576 bytes, with no effect. > >> >> > >> >> One possible theory is that maybe something in Linux doesn't allow > >> >> multiple requests to be issued in parallel and waits for each request > >> >> to be completed before issuing the next one? > >> > > >> > Linux NFS client can issue I/Os in parallel. Should be limited by number > >> > of RPC slots though. > >> > >> What controls the number of RPC slots? is there a tunable? Is there > >> something to monitor the usage? > > > > sysctl sunrpc.tcp_slot_table_entries (if you are using tcp) > > Its 16 > NFSv4 is tcp only > > I tried to bump the value to 128 - without effect - but the change is > not persistent across reboots. Is there something like Solaris > /etc/system which the kernel reads to set these values? Probably depends on your distro. Look at /etc/sysctl.conf if you have that file. > > Also, mountstats <mount-point> would be very helpful. > > I don't have that command. likely my test machine is too old Hmm, my RHEL6.4 has it. What nfs-utils package you have. Regards, Malahal. -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
