misc/157929: NFS slow read

[Christian]

>Number:         157929
>Category:       misc
>Synopsis:       NFS slow read
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jun 16 20:10:09 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Christian
>Release:        FreeBSD 8.2-RELEASE
>Organization:
Teleservice Bredband Skane AB
>Environment:
FreeBSD xxxxxxx.xxx.xxx 8.2-RELEASE FreeBSD 8.2-RELEASE #0: Thu Feb 17 02:41:51 UTC 2011     root at mason.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
Having problem with read over NFS, speed does not exceed 300Mbit in our environment. With SAMBA, SCP and other methods we get 900Mbit-1000Mbit in read throughput but when using NFS there seems to be a problem to exceed 300Mbit.
We are using ZFS in our environment but have tried to export a non-ZFS volume with no improvements at all.


Write speed is good, so if we reverse mount export in the reversed way on server a instead of server b we can write over NFS (in the same direction as we would read in our earlier tests) with a throughput at 900-1000Mbit.
>How-To-Repeat:
Running FreeBSD 8.2-RELEASE
# /etc/export:
/vol1   -maproot=root   192.168.x.x

# mount 192.168.x.x:/vol1 /mnt/vol1
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: