> Actually standalone WAL is required when you have either very small fast
> device (and don't want db to use it) or three devices (different in
> performance) behind OSD (e.g. hdd, ssd, nvme). So WAL is to be located
> at the fastest one.
> For the given use case you just have HDD and NVMe and DB and WAL can
> safely collocate. Which means you don't need to allocate specific volume
> for WAL. Hence no need to answer the question how many space is needed
> for WAL. Simply allocate DB and WAL will appear there automatically.
Yes, i'm surprised how often people talk about the DB and WAL separately
for no good reason.  In common setups bluestore goes on flash and the
storage goes on the HDDs, simple.

In the event flash is 100s of GB and would be wasted, is there anything
that needs to be done to set rocksdb to use the highest level?  600 I
ceph-users mailing list

Reply via email to