FAQ Search Today's Posts Mark Forums Read
» Video Reviews

» Linux Archive

Linux-archive is a website aiming to archive linux email lists and to make them easily accessible for linux users/developers.


» Sponsor

» Partners

» Sponsor

Go Back   Linux Archive > Redhat > Fedora User

 
 
LinkBack Thread Tools
 
Old 09-28-2012, 04:33 PM
Guido Winkelmann
 
Default NFS mounts on Fedora 17 hang when reading lots of data

Hi,

I am experiencing problems with NFS mounts locking up after some use on a
Fedora 17 machine. The symptoms are that all processes trying to access any
file will hang indefinitely. In ps, these processes are listed as being in
status D. There are no error messages, not even in dmesg.

When I unmount the NFS-share with umount -l (it won't work without the -l),
the processes will stay stuck but can be killed. In at least one case, I could
not even mount the share again after doing that. (The mount command would hang
indefinitely.)
(Indefinitely here means "I have waited several hours, and nothing has
happened".)

I cannot reliably reproduce the problem, but it seems to be happening more
often when reading a very large number (100000+) of 1 MB-sized files using a
large number (1000+) of concurrent requests over the NFS share. I have written
a script (originally for testing filesystem consistency using SHA1 checksums)
that does just that.

When the NFS lockup happens, the rest of the client machine keeps working,
except of course processes trying to access the share. (That includes things
like df).

The described problem has happened against two very different NFS servers:
Another Fedora 17 based server running on a Dell R210 II and an EMC VNX 5300.

The NFS protocol has been NFSv3 over TCP in all cases. I haven't yet tried to
repoduce the problem with UDP. NFSv4 is not really an option. (Because it
shows weird problems with chown and chmod.)

The kernel version on the client machine is 3.5.4-1.fc17.x86_64.

Does anybody have any idea what might be happening here or what I could do to
further debug the problem? Should I file a bug report?

Regards,
Guido

--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org
 
Old 09-28-2012, 05:00 PM
Tom Horsley
 
Default NFS mounts on Fedora 17 hang when reading lots of data

On Fri, 28 Sep 2012 18:33:06 +0200
Guido Winkelmann wrote:

> Does anybody have any idea what might be happening here or what I could do to
> further debug the problem? Should I file a bug report?

I have seen infinite numbers of problems with NFS over the years, and as far
as I know most of them got lots better when you could finally do TCP rather
than UDP connections. I think TCP is as good as it gets, but I still don't
trust NFS at all.

There is a possibility that the problem is at a lower level in the ethernet
driver. You could try using scp to copy the same sort of data and see if it
winds up with problems too. If so, that would probably mean ethernet driver.
--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org
 
Old 09-29-2012, 10:43 PM
guido
 
Default NFS mounts on Fedora 17 hang when reading lots of data

On Friday 28 September 2012 13:00:47 Tom Horsley wrote:
> There is a possibility that the problem is at a lower level in the ethernet
> driver. You could try using scp to copy the same sort of data and see if it
> winds up with problems too. If so, that would probably mean ethernet driver.

Hm, I haven't tried that, but when the described lockups happen, I can still
send and receive over that same network interface.

Guido

--
users mailing list
users@lists.fedoraproject.org
To unsubscribe or change subscription options:
https://admin.fedoraproject.org/mailman/listinfo/users
Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
Have a question? Ask away: http://ask.fedoraproject.org
 

Thread Tools




All times are GMT. The time now is 07:06 PM.

VBulletin, Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Relevant URLs by vBSEO ©2007, Crawlability, Inc.
Copyright 2007 - 2008, www.linux-archive.org