I'm not sure if it's good to ask at this place but still want to make sure that some one has a same issue as me.

Currently we're using Kolla Openstack (R version), and Gnocchi version is 4.3.2 (ubuntu-source).

The issue is, we always get below error trace in gnocchi-metricd after launched VM or uploaded images that let Ceilometer to create metrics in few environments.

https://pastebin.com/fPZSFWaE 

After few investigations, we found that this only happens on the environment which enabled cache tier in Ceph.

And also found the gnocchi cache pool only got 14 Bytes data inside, and no data inside the OSD pool one.

We tried remove the cache tier from gnocchi pool then restart the gnocchi services. Then everything become normal. Can saw Gnocchi work normally to write data into Ceph pool.

Does anyone had a same problem?

Eddie.