[ceph-users] Best osd scenario + ansible config?

Hello, I am deploying a new Nautilus cluster and I would like to know what would be the best OSD's scenario config in this case : 10x 6TB Disk OSDs (data) 2x 480G SSD previously used for journal and can be used for WAL and/or DB Is it better to put all WAL on one SSD and all DBs on the other one? Or put WAL and DB of the first 5 OSDs on the first SSD and the 5 others on the second one. A more general question, what is the impact on an OSD if we lose the WAL? The DB? Both? I plan to use EC 7+5 on 12 servers and I am OK if I lose one server temporarily. I have spare servers and I can easily add another one in this cluster. To deploy this cluster, I use ceph-ansible (stable-4.0). I am not sure how to configure the playbook to use SSD and disks with LVM. https://github.com/ceph/ceph-ansible/blob/master/docs/source/osds/scenarios… Is this good? osd_objectstore: bluestore lvm_volumes: - data: data-lv1 data_vg: data-vg1 db: db-lv1 db_vg: db-vg1 wal: wal-lv1 wal_vg: wal-vg1 - data: data-lv2 data_vg: data-vg2 db: db-lv2 db_vg: db-vg2 wal: wal-lv2 wal_vg: wal-vg2 Is it possible to let the playbook configure LVM for each disk in a mixed case? It looks like I must configure LVM before running the playbook but I am not sure if I missed something. Is wal_vg and db_vg can be identical (on VG per SSD shared with multiple OSDs)? Thanks for your help. Best regards, -- Yoann Moulin EPFL IC-IT