Hello Cephers,
During our testing, I found that the filestore throttling became a limiting 
factor for performance, the four settings (with default value) are:
 filestore queue max ops = 50
 filestore queue max bytes = 100 << 20
 filestore queue committing max ops = 500
 filestore queue committing max bytes = 100 << 20

My understanding is, if we lift the threshold, the response for op (end to end) 
could be improved a lot during high load, and that is one reason to have 
journal. The downside is that if there is a read following a successful write, 
the read might stuck longer as the object is not flushed.

Is my understanding correct here?

If that is the tradeoff and read after write is not a concern in our use case, 
can I lift the parameters to below values?
 filestore queue max ops = 500
 filestore queue max bytes = 200 << 20
 filestore queue committing max ops = 500
 filestore queue committing max bytes = 200 << 20

It turns out very helpful during PG peering stage (e.g. OSD down and up).

Thanks,
Guang


                                          
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