X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=src%2Fceph%2Fdoc%2Frados%2Foperations%2Fdata-placement.rst;fp=src%2Fceph%2Fdoc%2Frados%2Foperations%2Fdata-placement.rst;h=0000000000000000000000000000000000000000;hb=7da45d65be36d36b880cc55c5036e96c24b53f00;hp=27966b0dd98ac4e03dd18e101d1cf33daaf83ac4;hpb=691462d09d0987b47e112d6ee8740375df3c51b2;p=stor4nfv.git diff --git a/src/ceph/doc/rados/operations/data-placement.rst b/src/ceph/doc/rados/operations/data-placement.rst deleted file mode 100644 index 27966b0..0000000 --- a/src/ceph/doc/rados/operations/data-placement.rst +++ /dev/null @@ -1,37 +0,0 @@ -========================= - Data Placement Overview -========================= - -Ceph stores, replicates and rebalances data objects across a RADOS cluster -dynamically. With many different users storing objects in different pools for -different purposes on countless OSDs, Ceph operations require some data -placement planning. The main data placement planning concepts in Ceph include: - -- **Pools:** Ceph stores data within pools, which are logical groups for storing - objects. Pools manage the number of placement groups, the number of replicas, - and the ruleset for the pool. To store data in a pool, you must have - an authenticated user with permissions for the pool. Ceph can snapshot pools. - See `Pools`_ for additional details. - -- **Placement Groups:** Ceph maps objects to placement groups (PGs). - Placement groups (PGs) are shards or fragments of a logical object pool - that place objects as a group into OSDs. Placement groups reduce the amount - of per-object metadata when Ceph stores the data in OSDs. A larger number of - placement groups (e.g., 100 per OSD) leads to better balancing. See - `Placement Groups`_ for additional details. - -- **CRUSH Maps:** CRUSH is a big part of what allows Ceph to scale without - performance bottlenecks, without limitations to scalability, and without a - single point of failure. CRUSH maps provide the physical topology of the - cluster to the CRUSH algorithm to determine where the data for an object - and its replicas should be stored, and how to do so across failure domains - for added data safety among other things. See `CRUSH Maps`_ for additional - details. - -When you initially set up a test cluster, you can use the default values. Once -you begin planning for a large Ceph cluster, refer to pools, placement groups -and CRUSH for data placement operations. - -.. _Pools: ../pools -.. _Placement Groups: ../placement-groups -.. _CRUSH Maps: ../crush-map