[ceph-users] fault tolerant about erasure code pool

Hi all, I'm going to deploy a cluster with erasure code pool for cold storage. There are 3 servers for me to set up the cluster, 12 OSDs on each server. Does that mean the data is secure while 1/3 OSDs of the cluster is down, or only 2 of the OSDs is down , if I set the ec profile with k=4 and m=2. Thanks