From: Steve Dickson <SteveD@RedHat.com>
Subject: Re: nfsd tuning - please help me!
Date: Fri, 14 Feb 2003 06:33:08 -0500
Sender: nfs-admin@lists.sourceforge.net
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Here is a few suggestions I've seen floating around...
Your mileage my vary...

* Increased the number of server threads from the default 8 to 64.
   This is done by changing the value of RPCNFSCOUNT in /etc/init.d/nfs.

* Increased the size of the socket input queue buffers by adding the
   following two lines to /etc/ sysctl.conf:
    net.core.rmem_default = 262144
    net.core.rmem_max = 262144

*Increased the fragmented packet queue length upper and lower bounds:
    net.ipv4.ipfrag_high_thresh = 524288
    net.ipv4.ipfrag_low_thresh = 393216

Also make sure your network interfaces are full duplex...
You can use the mii-tool for that...

SteveD.

Alan Powell wrote:

>Linux NFS gurus: I need your help! I've spent the
>better part of the week trying to tune our NFS server.
>It's serving about 30Mbit/sec sustained, but the
>latency for serving NFS requests is high. When I
>access an NFS mount from a client machine, it can
>sometimes take several seconds to do even a simple
>directory listing. However, doing the same operations
>on the NFS server locally is always fast, even if I'm
>doing the operation from an NFS client that is under
>minimal load. So I'm pretty sure that the problem is
>NFS server specific. Furthermore, I'm pretty sure that
>this is not a hardware issue, so my question is if we
>are just running the Linux NFS daemon up to its
>limits? WAt this point we're very close to buying a
>NetApp filer to alleviate the problem, b/c I've heard
>some amazing stats from their salespeople, but I
>wanted to check with you guys first. Thank you!
>
>Here's some more info:
>- We're using the latest RH 7.3 kernel
>(2.4.18-24.7.xsmp) on both the server and clients.
>- We use only NFS v3.
>- For the most part of the day, we're serving about
>100 random 30KB file reads per second (minimal
>writes), resulting in 30Mbit transfer.
>- We are not hardware constrained (CPU is 90% idle,
>and the disks perform fine when doing local file
>operations). The latency only occurs for NFS
>operations.
>- There are no network issues (there are hardly any
>retransmissions according to nfsstat). Also, using
>ttcp to test the network connection, we're able to
>utilize the remaining 70Mbit on the ethernet card.
>- We have a max limit of 32 NFS daemon processes, and
>according to /proc/net/rpc/nfsd, that is more than we
>need.
>- NFS is mounted with the following options, and
>increasing [rw]size beyond 8192 has made no
>difference: rw,hard,rsize=8192,wsize=8192,actimeo=120 
>- Adjusting [rw]mem_default and [rw]mem_max in
>/proc/sys/net/core beyond the default 64KB has made no
>difference.
>
>I rebooted the NFS server about 20 hours ago, and here
>are nfsstat and iostat numbers for it since the
>counters were cleared out 20 hours ago:
>
>[root@server etc]# nfsstat -s
>Server rpc stats:
>calls      badcalls   badauth    badclnt    xdrcall
>47303390   0          0          0          0       
>
>Server nfs v3:
>null       getattr    setattr    lookup     access    
>readlink   
>0       0% 12498418 26% 16824   0% 7556878 15% 224714 
>0% 54      0% 
>read       write      create     mkdir      symlink   
>mknod      
>26663116 56% 225950  0% 19573   0% 1       0% 0      
>0% 0       0% 
>remove     rmdir      rename     link       readdir   
>readdirplus
>7936    0% 0       0% 14880   0% 248     0% 36450   0%
>605     0% 
>fsstat     fsinfo     pathconf   commit     
>14      0% 37      0% 0       0% 37766   0% 
>
>
>[root@server etc]# iostat -x
>Linux 2.4.18-24.7.xsmp (server.domain.com)  02/13/2003
>
>avg-cpu:  %user   %nice    %sys   %idle
>           0.27    0.01    7.78   91.94
>
>Device:    rrqm/s wrqm/s   r/s   w/s  rsec/s  wsec/s  
> rkB/s    wkB/s avgrq-sz avgqu-sz   await  svctm 
>%util
>/dev/rd/c0d0
>           280.34   6.17  0.00  0.00 5172.83   67.25 
>2586.41    33.63     0.00     0.29    0.00   0.00 
>10.37
>
>
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