Kernel Panics Ubuntu Server 11.04 and Samba

[Alvin]

On Wednesday 25 May 2011 00:23:22 zongo saiba wrote:
> Hi  Guys,
> 
> I have been running Ubuntu Server 11.04 for a couple of weeks with a Samba
> server and it is running great. The other day a client win7 tried to do a
> backup to the allocated Samba share and the server kernel-panicked on me.
> 
> Since then, every single time win7 clients are trying to do backups on
> allocated shares through Samba protocol, the server kernel-panicked and I
> have to reboot it.
> 
> The only reason I found in the logs for the KP :" kernel panic - not
> syncing: fatal exception in interrupt".
> 
> I immediately tested my ram with memtest-86 and all is ok
> 
> I mounted two external usb drives on the shares and tried to run the
> backups on the usb drives and the issue is identical. The server KP every
> single time.
> 
> I then run HDD test on both external USB drives and internal drive of the
> server and all is ok.
> 
> I have searched google for an answer but to  no avail. All the posts
> referred back to a potential hardware issue on the server. Hardware wise,
> my server has no issues.
> 
> Any help is much appreciated on sorting the issue as I have no idea on
> where to look for a solution.

I've given up on using Ubuntu as a file server solution. It can't handle high 
disk I/O. I'd still like to know where the problem lies though.

Have you only been testing with samba? You could try installing rsync[1]. 
(deltacopy) on Windows and copy a large amount of data over to the Ubuntu 
server. Make sure you can copy at high speed.

Do you have more information about your system?
- What's the memory usage during a copy?
- Do you use LVM? Do you have snapshots. (snapshots would explain the issue)
- Are there any more messages in /var/log/kern.log?

[1] https://bugs.launchpad.net/bugs/750359
    Kernel panics under load