[lustre-discuss] Large file read performance degradation from multiple OST's
Vicker, Darby (JSC-EG311)
darby.vicker-1 at nasa.gov
Fri May 26 14:19:54 PDT 2017
>> 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?
I've verified that the client compiled with the latest master branch code still reads very fast on 1 OST and slow multiple OSTs. The behavior is the same with fast_read=0 (also with the master branch client). We'll try to isolate the problem with a git bisect.
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