数据量规划
计划数据年增涨量150TB，存储初始容量 = 数据年增涨量×3 = 450TB
硬件规划
ceph-osd
sas 4TB *12= 48TB (DATA)
ssd 256GB *1 (OS)
ssd 256GB *2 (WAL+DB)OSD: 1 per HDD = 12 OSD
CPU: 0.5 cores per HDD = 6 cores
RAM: 5GB per OSD = 64GB
ceph-ansible & ceph-mon & ceph-mgr & ceph-radosgw
ssd 256GB *1 (OS)
CPU: 1 core
RAM: 1GB
DISK: 50GB
容量300TB集群需要：4台低配服务器（单cpu/16G/256GB），9台高配服务器（双C/64G/256GB+4TB）
ceph规划
osd_pool_default_pg_num: ？ -> 600
osd_pool_default_pgp_num: ？-> 600
osd_pool_default_size: 3
osd_pool_default_min_size: 1
total pgs = (Total_number_of_OSD * 100) / max_replication_count
pgs = 12 * 9 * 100 / 3 = 3600
pg num = total pgs / pool_number
规划6个pool的话: pg = 3600 / 6 = 600
