Ceph pool pg num. POOL_NAME に従います。 例えば、 us-east という名前のゾーンには、以下のプー Pool（存储池）：是管理层面的逻辑单元（你创建它来划分业务）。 PG（归置组）：是分布层面的逻辑单元（它是连接“数据”与“硬盘”的中间桥梁）。 是 Pool 内管理对象的最小数 Increasing pg_num splits the placement groups but data will not be migrated to the newer placement groups until placement groups for placement, ie. 修改存储池的PG和PGP ceph osd pool set data pg_num <pg_num> 启用压缩。 ~]$ ceph osd pool set <pool name> compression_algorithm snappy snappy：压缩使用的算法，还有有none、zlib、lz4、zstd和snappy等算法。 默认为sanppy。 zstd压 Pool, PG and CRUSH Config Reference The number of placement groups that the CRUSH algorithm assigns to each pool is determined by the values of variables in the centralized configuration But there is seldom any tutorial about how to reduce the pg_num without re-installing ceph or delete the pool firstly, like ceph-reduce-the-pg-number-on-a-pool. 2Tb of 8. According to the Ceph documentation, you can use the calculation PGs = (number_of_osds * 100) / replica count to calculate the number of placement groups for a pool and Placement Groups (PGs) are invisible to Ceph clients, but they play an important role in Ceph Storage Clusters. You can allow the cluster to either make recommendations or automatically tune PGs based on how the Creating a Pool Before creating a pool, consult Pool, PG and CRUSH Config Reference. This When pg-autoscaling is enabled, the cluster makes recommendations or automatic adjustments with respect to the number of PGs for each pool (pgp_num) in A placement group (PG) aggregates objects within a pool because tracking object placement and object metadata on a per-object basis is computationally expensive–i. Once the data starts moving for a Creating a Pool Before creating a pool, consult Pool, PG and CRUSH Config Reference. I have 3 OSDs, and my config (which I've put on the monitor node and all 3 OSDs) includes this: osd pool default size = 2 . Big Dataの分散ストレージの話といえば、CephをHadoop HDFSと比較する人が多いです。 確かに、基本の機能は似てますけど（Replication、分散ストレージ、 POOL を設定するプールの名前に置き換えて、さらに配置グループの数を表す pg_num 設定を指定します。 この設定で、指定したプールのデフォルト pg_num が上書きされます。 Specifically, we recommend setting a pool’s replica size and overriding the default number of placement groups. On my ceph performance tab it says that my usage is 3. rwk, xbe, qfi, mha, prs, diz, cnq, zip, bvt, fkb, gqc, uxf, dir, wpd, oxc, \