Is metadata on SSD or bluestore cache better?

4 Apr 2021

      Hi,

I hope this mailgroup is ok for this kind of questions, if not please 
ignore.

I'm currently in the process of planning a smaller ceph cluster mostly 
for cephfs use.

The budget still allows for some SSD's in addition to the required 
harddisks.

I see two options on how to use  those,

a) Make SSD only pools for the cephfs metadata

b) Give every OSD a SSD for the bluestore cache

I was not able to find any suggestions or benchmarks so far, does anyone 
has further resources or insight into those options?

Greetings,

Kai

Kai Börnert