NFS Server reaches much too High load

[Jürgen Sauer]

jojo@pc2:~$ lsb_release -rd
Description: Ubuntu 10.04.2 LTS
Release: 10.04

Found on this kernels:
-rw-r--r-- 1 root root 4174144 2011-03-02 03:47 /boot/vmlinuz-2.6.32-30-generic-pae
-rw-r--r-- 1 root root 4427232 2011-01-26 01:49 /boot/vmlinuz-2.6.35-25-generic-pae
-rw-r--r-- 1 root root 4669168 2011-03-29 00:57 /boot/vmlinuz-2.6.38-7-generic-pae

Circumstances:
- NFS-Kernel-Server
- Gigabit NIC
- Client Lucid 10.04.2 LTS

Client mounted a share from the server.
i.e.: mount server:/video /mnt -o rsize=32768,wsize=32768

Doing this on Client:
root@vdr:/mnt# dd if=/dev/zero bs=1M of=zero.file.de count=1024
1024+0 Datensätze ein
1024+0 Datensätze aus
1073741824 Bytes (1,1 GB) kopiert, 73,4087 s, 14,6 MB/s

causes a load average of:
top - 11:54:00 up 23:26, 4 users, load average: 6.32, 1.87, 0.79

Compared to the same dir exported via samba:
top - 11:57:52 up 23:30, 4 users, load average: 1.97, 1.53, 0.86
root@vdr:/video# dd if=/dev/zero bs=1M of=zero2.file.de count=1024
1024+0 Datensätze ein
1024+0 Datensätze aus
1073741824 Bytes (1,1 GB) kopiert, 64,4172 s, 16,7 MB/s

And nearly a deney of service is if bigger files are copied:
NFS-Kernel-Server-Share, Server:
top - 12:09:06 up 23:42, 3 users, load average: 16.05, 5.80, 2.86
Client/vdr:
root@vdr:/mnt# rsync -aP filme/vdr/%Unser_taeglich_Gift .
sending incremental file list
%Unser_taeglich_Gift/
%Unser_taeglich_Gift/2011-03-26.14.25.99.99.rec/
%Unser_taeglich_Gift/2011-03-26.14.25.99.99.rec/001.vdr
2097532591 100% 7.16MB/s 0:04:39 (xfer#1, to-check=6/9)
[copy removed after test]

On Samba Samba Share:
top - 12:12:29 up 23:45, 3 users, load average: 2.09, 4.23, 2.87
auf dem client:
root@vdr:/video# rsync -aP filme/vdr/%Unser_taeglich_Gift .
sending incremental file list

%Unser_taeglich_Gift/
%Unser_taeglich_Gift/2011-03-26.14.25.99.99.rec/
%Unser_taeglich_Gift/2011-03-26.14.25.99.99.rec/001.vdr
729841664 34% 8.45MB/s 0:02:38

Look like an load regression on copying big files on the nfs-client. Compared to same file export
the NFS-kernel-server load is up to 8-times bigger.

This behavior had frozen/DOS a couple servers here.

J. Sauer

ProblemType: Bug
DistroRelease: Ubuntu 10.04
Package: linux-image-2.6.35-25-generic-pae 2.6.35-25.44~lucid1
ProcVersionSignature: Ubuntu 2.6.35-25.44~lucid1-generic-pae 2.6.35.10
Uname: Linux 2.6.35-25-generic-pae i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Tue Apr 5 12:29:20 2011
ProcEnviron:
 LANGUAGE=
 PATH=(custom, user)
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-lts-backport-maverick