Summary: NFS speedup

Last week I'd asked for help on speeding up NFS over gigabit for large 
file transfers (several sybase databases over 100-500GB each)
dumped via NFS to v240s.

Thanks to Joe Fletcher and Vitaly Porotikov for useful information.
Joe suggested that I just dump my v880's and go to x64.
Vitaly suggested jumbo frames.
I can't do either at the moment but I can look at their other suggestions:

Joe suggested tweaking maxphys

set maxphys=1048576
set md:md_maxphys=1048576

which I already had set and he has the following tweaks in a startup 
script:

#!/bin/sh
#
#
# Setup for Giga Bit Ethernet
#

case "$1" in
'start')
        /usr/sbin/ndd -set /dev/tcp tcp_xmit_hiwat 65535
        /usr/sbin/ndd -set /dev/tcp tcp_recv_hiwat 65535
        /usr/sbin/ndd -set /dev/udp udp_xmit_hiwat 65535
        /usr/sbin/ndd -set /dev/udp udp_recv_hiwat 65535
        /usr/sbin/ndd -set /dev/tcp tcp_max_buf 262144
        /usr/sbin/ndd -set /dev/tcp tcp_deferred_ack_interval 100
        /usr/sbin/ndd -set /dev/tcp tcp_dupack_fast_retransmit 2
        /usr/sbin/ndd -set /dev/tcp tcp_slow_start_initial 4
                echo gbit_ndd done
        ;;
*)
        echo "Usage: /etc/init.d/gbit_ndd { start | stop }"
        ;;
esac
exit 0

In his testing (he sent me the results) he get's full speed gig-e 
(100MB/sec) over the wire.
------
Vitaly sent the following tips addressing NFS tuning and TCP tuning:

2. adjust nfs kernel:

   - nfs3_nra -> 16~32
   - nfs3_bsize -> 65536 and hence you can increase rsize (nfs mount 
option) -> 65536 
   - nfs3_max_transfer_size -> 65536 
   - clnt_max_conns -> 16~32
   - sq_max_size -> 25~100

 use 'mdb -kw' to change on the fly

 3. adjust tcp parameters:

   tcp_max_buf -> 1~4MB
   tcp_cwnd_max->1~4M
   tcp_xmit_hiwat -> 131072~1M
   tcp_recv_hiwat -> 131072~1M
   tcp_wscale_always -> 1

 use ndd to change
 
 4. use 'nocto', 'noac' option for nfs mount
 
 
Dean Ross-Smith
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