Heavy Bug Encountered on NFSv4 Server

[Thomas Hoppe]

Hi,

that's good to know how NFS works here!

I don't think that it is a networking issue
because the site is not that big, that it could
saturate even a 10 Mbit line. I think it's
a database problem.

Another question for is how to tweak the settings for the clinet side
caching... all I know is that NFS, in theory, caches
data heavily, but I can find no resource on how
to modify say the cache size... I think NFSv4 is in
general missing a good documentation.

many many thanks

J. Bruce Fields schrieb:
> On Wed, Jun 20, 2007 at 11:01:37PM +0200, Thomas Hoppe wrote:
>   
>> it seems like this problem is gone somehow.
>> Just to sum it up:
>>
>> I just switched to another release of the Gentoo 2.6.20 Kernel
>> and since then, the error did not reoccur.
>> I don't think that the Gentoo guys mess with the NFS code
>> so the only explanation for me would be that in the vanilla
>> kernel ther was a fix for something NFS 4 related.
>>     
>
> Hm.  OK, well, let us know if you see it again or figure out anything
> more.
>
>   
>> How does an NFS 4 server handle multiple concurrent reads
>> on a single file? Say computer A is reading a file on
>> an NFS server. I have the feeling that during the read,
>> other Computers are blocked/queued from reading that file.
>> Is that assumption true?
>>     
>
> No.  The reads should all be able to proceed concurrently.
>
>   
>> My concrete scenario is that I have a webserver which exports
>> the web root to 6 webservers and whenever the load is high
>> I see that images load rather laggy.
>>     
>
> And its the same image file, or a small number of image files, that are
> being read?  Do you suspect a problem with NFSv4 in particular?  (Have
> you seen the same behavior with NFSv3?)  Is it possible the network
> between the file server and its clients (the webserver) is maxed out?
>
> --b.
>
>
>   

-- 
Thomas Hoppe
Richard-Wagner-Str. 35
73207 Plochingen
Phone:  +49.(0).7153.615928
Mobile: +49.(0).176.27233907

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