[ceph-users] Nautilus 14.2.10 mon_warn_on_pool_no_redundancy

Hi All, I really like the idea of warning users against using unsafe practices. Wouldn't it make sense to warn against using min_size=1 instead of size=1. I've seen data loss happen with size=2 min_size=1 when multiple failures occur and write have been done between the failures. Effectively the new warning below says "It is not considered safe to run with no redundancy". Which is true, but when failure occurs or maintenance is executed, with size=2 and min_size=1, as soon as data is written, there might not be data redundancy for that newly written data. A failure of an OSD at that moment would result in data loss. Since you cannot run size=1 with min_size > 1, this use-case would also be covered. I understand this has implications for size=2 when executing maintenance, but I think most people are not aware of the risks they are taking with min_size=1. Those that are aware can suppress the warning. * Ceph will issue a health warning if a RADOS pool's `size` is set to 1   or in other words the pool is configured with no redundancy. This can   be fixed by setting the pool size to the minimum recommended value   with::     ceph osd pool set <pool-name> size <num-replicas>   The warning can be silenced with::     ceph config set global mon_warn_on_pool_no_redundancy false -- kind regards, Wout 42on