metadata pool : size growing

[florent@xxxxxxxxxxx (Florent B)]

Hi all,

I use CephFS and I am wondering what does "metadata" pool contains exactly ?

Its size is growing (multiple GB).

It seems that it stores all operations occurring in CephFS, but is it
totally necessary ?

When a MDS is taking failover, does it have to read all content of
metadata pool (replay state) ?

I haven't found architecture information of this pool, can someone tell me ?

Thank you.

Florent