[ceph-users] cephfs kernel client - page cache being invaildated.

jesper at krogh.cc jesper at krogh.cc
Sat Nov 3 02:31:24 PDT 2018

> I suspect that mds asked client to trim its cache. Please run
> following commands on an idle client.

In the mean time - we migrated to the RH Ceph version and deliered the MDS
both SSD's and more memory and the problem went away.

It still puzzles my mind a bit - why is there a connection between the
"client page cache" and the MDS server performance/etc. The only argument
I can find is that if the MDS cannot cache data, then and it need to go
back and get metadata from the Ceph metadata poll then it exposes
data as "new" to the clients, despite it being the same. - if that is
the case, then I would say there is a significant room for performance
optimization here.

> If you can reproduce this issue. please send kernel log to us.

Will do if/when it reappears.

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