Re: NFS server slow when more clients access it

["nate" <debian-user@aphroland.org>]

Lukas Kubin said:


> Yes -- point #4 above. When I use the kernel server then the client can't
> see directories into that was mounted something on the server. Let's say
> I've mounted /dev/sdb1 as /home on the server. Then I can see the content
> of /home on the server but not on the client.

so you mean you can't see sub-mounts? that is:

you mount /  but /home is another filesystem and you can't see whats
on /home? in my experience this is perfectly normal operation. I believe
solaris does this as well.

>
>> What kernel(on both client & server)?
>
> 2.4.18 on server and 2.4.19 to boot the client.
>

I would increase the # of nfs procs on the server. for the userspace
server it looks like it is different. according to the manpage
for rpc.nfs you specify the numprocs manually in the init script:

       /usr/sbin/rpc.nfsd [ -f exports-file ] [ -d facility ]
       [ -P port ] [ -R dirname ] [ -Fhlnprstv ] [ --debug facil�
       ity ] [ --exports-file=file ] [ --foreground ] [ --help ]
       [ --allow-non-root ] [ --re-export ] [ --pub�
       lic-root dirname ] [ --no-spoof-trace ] [ --port port ]
       [ --log-transfers ] [ --version ] [ numservers ]


but it looks to be buggy:
      numcopies
              This  is  an experimental feature that lets you run
              several instances of nfsd in parallel. When given a
              value of numcopies greater than one, nfsd will fork
              as many times as specified by this value.  However,
              the  servers  do  not  share  a  common file handle
              cache, which makes certain file operations impossi�
              ble.

              For this reason, nfsd will disallow all write oper�
              ations when invoked with this option. Although this
              is very limiting, this feature may still prove use�
              ful for exporting public FTP areas or  Usenet  News
              spools.

I use this feature on both solaris and FreeBSD, what I'd do
in the init script is something like:

NUMSERVERS=15


[..]
start-stop-daemon --start --oknodo --quiet --exec /usr/sbin/rpc.nfsd --
$NUMSERVERS

(the above is probably line-wrapped so be sure its not linewrapped on your end)

beyond that, you'll need the kernel-space server most likely it is
much faster then the userspace server. Which of course means you may
have to alter the filesystem layout of the server.

nate