NFS copy - force not using cash ?

[MoshiachNow]

HI,

When running some performance test I copy a file from the NFS mounted volume to my local volume - the second copy of the same file is too fast - it's coming from my local NFS client cash.This ruins my test results.

Can I run the cp command and force it to use the real copy each time - not using it's cash ?

"Long live king Moshiach !"

http://www.7for70.com/

 

[sbix]

No way, unless you don't dismount each time the remote resource from your system ..... I think.
Indeed AIX is not cheating on your test ... only doing it's work.
An idea could be to measure the time not the 1st time and then the second one ... but between 2nd time and 3rd.

 

[MoshiachNow]

Thanks,

I have ended up remounting the remount FS each time...

"Long live king Moshiach !"

http://www.7for70.com/

 

[unixfreak]

I think you can set this with vmtune but I can't find it right now.

Cheers

 

[sbix]

Unixfreak ... yes probably to modify some setup with vmtune can prevent NFS caching ... but this is avoiding AIX to perform a well done job.
IMO levw should sample the 2 results (1st attempt and the avg of other ones) ... because it's the real scenario.
Not speaking about the memory usage on the exporting system can vary depending on it's workload, so it's extremly dependable the results even for the other run of the test