Re: Occassional "permission denied" in the middle of a large transfer over NFS

On 08/07/2012 00:26, Rick Macklem wrote:
> Vincent Hoffman wrote:
>>
>> Hi Rick,
>>
>> I'm afraid this didnt make any real difference for me.
>> Since I couldnt test it on the live system I tried it on a test vm.
>> on the vm (nfs server) I set a looping mount/umount
>> while true ; do mount /dev/md0 /mnt/tmp ; sleep 1 ; umount /mnt/tmp ;
>> done
>>
>> and on the client I set a loop of tars of large directorys to the nfs
>> mount running under time to see how well it survived. Then replicated
>> the test with the patch and without.
>>
> Just to confirm, you patched both the kernel and mountd and replaced both
> on the server?
>
> Also, I'm not sure how ZFS handles it's exports. I can't remember if you've
> tried an exported UFS volume. It might be something ZFS specific?
>
> rick

Hi Rick,
  
yes I patched both the kernel and mountd, rebuilt kernel and world (to
be sure), added the -S flag to mountd in rc.conf and rebooted.
This is a test VM running -CURRENT and is only exporting  a ufs2
filesystem.
(11:43:05 <~>) 0 $ cat /etc/exports
/usr/local/export -maproot=root -alldirs  XX.XX.XX.XX

Client is a 8.3-RELEASE box but I see the same with linux clients.
(I can confirm that it works fine when I am not running the mount/umount
loop)


The production system has been fine since I removed the SIGHUP call in
mount.c so thanks for that suggestion.


Vince
>
>> [root_at_seaurchin ~]# ministat nopatch.txt atomicpatch.txt
>> x nopatch.txt
>> + atomicpatch.txt
>> +--------------------------------------------------------------------------------------------------+
>> |
>> *
>> |
>> |
>> *
>> |
>> |
>> x*
>> |
>> |   xx*
>> x
>> |
>> |  +x**
>> xx
>> |
>> |  **** xxx
>> x
>> |
>> |  **** xxx +x+
>> +
>> |
>> |  ****+*xx +x+ x
>> +
>> |
>> |  ****+*x****++++x + +
>> x |
>> |  *************+*xx+ +++x * x
>> x |
>> |  ****************x**++*x+***x+ x*+ x ++*+ + x+ +x +
>> + +|
>> |||_______M_M_A__A_______|______|
>> |
>> +--------------------------------------------------------------------------------------------------+
>> N Min Max Median Avg Stddev
>> x 101 1.25 106.8 14.08 21.892178 22.196005
>> + 101 1.21 186.93 18.46 27.995842 30.523218
>> No difference proven at 95.0% confidence
>>
>>
>> (excuse wrapped ascii art)
>>
>> I think I'll have a look at the nfse patch set and see how that
>> performs.
>>
>> Thanks for all your work on NFS on FreeBSD.
>>
>> Vince
>>
>>>>> Also, you could easily hack mount.c so that it doesn't send a
>>>>> SIGHUP
>>>>> to mountd (which causes the exports to be reloaded) every time a
>>>>> local
>>>>> fs is mounted.
>>>> True and I may have to do that for the production NAS for the time
>>>> being.
>>>> Thanks for looking at this.
>>>>
>>>> Vince
>>>>> rick
>>>>>
>>>>>>> thanks, Vince
>>
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