1 files changed, 123 insertions, 0 deletions
diff --git a/doc/rados/operations/erasure-code-jerasure.rst b/doc/rados/operations/erasure-code-jerasure.rst
new file mode 100644
index 000000000..8a0207748
--- /dev/null
+++ b/doc/rados/operations/erasure-code-jerasure.rst
@@ -0,0 +1,123 @@
+============================
+Jerasure erasure code plugin
+============================
+
+The *jerasure* plugin is the most generic and flexible plugin, it is
+also the default for Ceph erasure coded pools. 
+
+The *jerasure* plugin encapsulates the `Jerasure
+<https://github.com/ceph/jerasure>`_ library. It is
+recommended to read the ``jerasure`` documentation to
+understand the parameters. Note that the ``jerasure.org``
+web site as of 2023 may no longer be connected to the original
+project or legitimate.
+
+Create a jerasure profile
+=========================
+
+To create a new *jerasure* erasure code profile:
+ 
+.. prompt:: bash $
+
+   ceph osd erasure-code-profile set {name} \
+     plugin=jerasure \
+     k={data-chunks} \
+     m={coding-chunks} \
+     technique={reed_sol_van|reed_sol_r6_op|cauchy_orig|cauchy_good|liberation|blaum_roth|liber8tion} \
+     [crush-root={root}] \
+     [crush-failure-domain={bucket-type}] \
+     [crush-device-class={device-class}] \
+     [directory={directory}] \
+     [--force]
+
+Where:
+
+``k={data chunks}``
+
+:Description: Each object is split in **data-chunks** parts,
+              each stored on a different OSD.
+
+:Type: Integer
+:Required: Yes.
+:Example: 4
+
+``m={coding-chunks}``
+
+:Description: Compute **coding chunks** for each object and store them
+              on different OSDs. The number of coding chunks is also
+              the number of OSDs that can be down without losing data.
+
+:Type: Integer
+:Required: Yes.
+:Example: 2
+
+``technique={reed_sol_van|reed_sol_r6_op|cauchy_orig|cauchy_good|liberation|blaum_roth|liber8tion}``
+
+:Description: The more flexible technique is *reed_sol_van* : it is
+              enough to set *k* and *m*. The *cauchy_good* technique
+              can be faster but you need to chose the *packetsize*
+              carefully. All of *reed_sol_r6_op*, *liberation*,
+              *blaum_roth*, *liber8tion* are *RAID6* equivalents in
+              the sense that they can only be configured with *m=2*. 
+
+:Type: String
+:Required: No.
+:Default: reed_sol_van
+
+``packetsize={bytes}``
+
+:Description: The encoding will be done on packets of *bytes* size at
+              a time. Choosing the right packet size is difficult. The
+              *jerasure* documentation contains extensive information
+              on this topic.
+
+:Type: Integer
+:Required: No.
+:Default: 2048
+
+``crush-root={root}``
+
+:Description: The name of the crush bucket used for the first step of
+              the CRUSH rule. For instance **step take default**.
+
+:Type: String
+:Required: No.
+:Default: default
+
+``crush-failure-domain={bucket-type}``
+
+:Description: Ensure that no two chunks are in a bucket with the same
+              failure domain. For instance, if the failure domain is
+              **host** no two chunks will be stored on the same
+              host. It is used to create a CRUSH rule step such as **step
+              chooseleaf host**.
+
+:Type: String
+:Required: No.
+:Default: host
+
+``crush-device-class={device-class}``
+
+:Description: Restrict placement to devices of a specific class (e.g.,
+              ``ssd`` or ``hdd``), using the crush device class names
+              in the CRUSH map.
+
+:Type: String
+:Required: No.
+
+``directory={directory}``
+
+:Description: Set the **directory** name from which the erasure code
+              plugin is loaded.
+
+:Type: String
+:Required: No.
+:Default: /usr/lib/ceph/erasure-code
+
+``--force``
+
+:Description: Override an existing profile by the same name.
+
+:Type: String
+:Required: No.
+