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

[Daniel Kobras]

Hi!

On Wed, May 24, 2017 at 04:04:00PM +0000, Vicker, Darby (JSC-EG311) 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.

The fast_read feature has been added to the client-side read path between 2.8 and 2.9. So for starters it might
be worthwhile to re-run the test on a 2.9 client with fast_read=0?

Kind regards,

Daniel