More on high i/o load wedging Fedora 10

[Robin Laing]

Eric Sandeen wrote:
> Robin Laing wrote:
>> Eric Sandeen wrote:
>>> Chuck Forsberg WA7KGX N2469R wrote:
>>>> I reformatted the backup drive with ext2 to see if that made any
>>>> difference.  Fedora still wedged during the backup, twice.
>>> When/if you gather the info I requested - sysrq 'w' output, which will
>>> actually help identify & resolve the issue instead of speculating about
>>> it, please file a bug against the kernel, attach the info I asked for,
>>> and I'll see it that way.  I probably won't be following these threads
>>> further.
>>>
>>> -Eric
>>>
>> And when you do, post the details to this list.
>>
>> I ask that as my F10 machine is going into a total freeze during backups 
>> as well.  The only item of what happened was a message in messages about 
>> a kernel oops.
> 
> What is the number for the bug you filed?
> 
>> I thought it may be related to the EXT4 issues and I am in the process 
>> of dumping EXT4 after reading many reports of data loss.
> 
> Please don't.  Please at *LEAST* report the bug(s) first - with details.
> 
> Guys, reporting vague errors on this list and then not following up with
> any useful information - especially when specific, simple steps are
> requested from developers who could *fix* it - is just wasting people's
> time and bandwidth.
> 
> For what it's worth, I assume your "many reports of data loss" are
> probably related to the recent slashdot/lwn/launchpad/whatever posting.
> 
> I won't rehash all the details of that, but patches are now in f10 and
> f11 to make ext4 behave a bit more like ext3, even when applications
> aren't doing an fsync(); on their data.  I do not expect that you will
> be at a large risk of data loss with ext4 on Fedora.
> 
> Thanks,
> -Eric
> 
> 

I always will report bugs if I can get the details.  It is almost 
useless to report bugs if you don't have any details to post with it as 
there is a request for more details.

It takes time to learn what tools to use to find issues.  I just read an 
IBM paper on tracing problems using iostat.  I also found dstat at the 
same time.  It is IO related as the problems all come from using or 
writing to a hard drive.  It has also gotten worse and may be related to 
the latest kernel.

My dumping EXT4 is more due to reports that I have read about data loss 
due to the procedure for write delays.  I have run into the issue of 
losing my kde config files as reported by others on the net already.

http://www.advogato.org/person/mjg59/diary/195.html
http://www.h-online.com/open/Possible-data-loss-in-Ext4--/news/112821
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/317781?comments=all

I am also dumping EXT4 as I am trying to trace the issue with 
locking/freezing computer and I don't need data losses.

As it stands, I did get a kernel oops last night that didn't crash my 
system and was logged in messages.  I was using a tty session so this 
could be why the system didn't totally freeze.

I have not had time to look through it and to see where it should be 
posted.  It is related to USB as it occurred when I unplugged my USB 
drive that I was restoring data from.  It was late and I was tired so I 
want to check things on the system before going further.

There is an issue with filing kernel related bugs if the kernel is 
tainted because of Nvidia drivers.  I have been told before that I need 
to remove the driver before filing a bug.  Well that is hard to do when 
3D is needed on the computer with the problem.

I just tried the sysrq 'w' but I don't have that command on my machine 
at work.



-- 
Robin Laing