[lustre-discuss] Large file read performance degradation from multiple OST's

[Dilger, Andreas]

On May 24, 2017, at 10:04, Vicker, Darby (JSC-EG311) <darby.vicker-1 at nasa.gov> wrote:
> 
> I tried a 2.8 client mounting the 2.9 servers and that showed the expected behavior – increasing performance with increasing OST's.  Two things:
>  
> 1.  Any pointers to compiling a 2.8 client on recent RHEL 7 kernels would be helpful.  I had to boot into an older kernel to get the above test done. 
>  
> 2. Any help to find the problem in the 2.9 code base would also be helpful. 

One option would be to run "git bisect" of the client build to see if you can isolate this performance regression to a particular patch.  It would also be worthwhile to run a test with the git master client since this problem may already be fixed.  The master branch is very close to final code freeze for the 2.10 release, so should be stable enough for your testing, and if it isn't then we should also know about that.

Cheers, Andreas
--
Andreas Dilger
Lustre Principal Architect
Intel Corporation