initial code repo

This patch creates initial code repo.

For ceph, luminous stable release will be used for base code,
and next changes and optimization for ceph will be added to it.

For opensds, currently any changes can be upstreamed into original
opensds repo (https://github.com/opensds/opensds), and so stor4nfv
will directly clone opensds code to deploy stor4nfv environment.
And the scripts for deployment based on ceph and opensds will be
put into 'ci' directory.

Change-Id: I46a32218884c75dda2936337604ff03c554648e4
Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/src/ceph/doc/rados/operations/data-placement.rst b/src/ceph/doc/rados/operations/data-placement.rst
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+=========================
+ 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