ceph config recommendation

[Danielg]

hi forum

we have 3 hosts in a running cluster. there is a seperate 10gbps storage network attached to all hosts.
each host have 2x 1tb ssd disks. out goal is a ha storage with 1 host failure tolerance.

is it better to to have a raid0 configuration on each host and attach this raid to one osd, or create one osd for each ssd?

and for pool, what are best settings for size / min size and pg_num?
for my understanding, size means replicas on different osds, right? but what means min size?

thanks in advance for any help.

regards,
daniel

 

[Alwin]

is it better to to have a raid0 configuration on each host and attach this raid to one osd, or create one osd for each ssd?

Avoid RAID, Ceph wants its disk under control.

and for pool, what are best settings for size / min size and pg_num?

https://pve.proxmox.com/pve-docs/chapter-pveceph.html#pve_ceph_pools

for my understanding, size means replicas on different osds, right? but what means min size?

size is the count of replicas, min_size is the count of replicas where data is still served, any PG having less gets the pool into read-only.

Here some more information on the topic.
https://forum.proxmox.com/threads/proxmox-ceph-cluster-advice.42891/#post-205912
https://forum.proxmox.com/threads/ceph-raw-usage-grows-by-itself.38395/#post-189842