From 4cf22e195ab367eb65f95c2578d06919ebcd108f Mon Sep 17 00:00:00 2001 From: Zac Dover Date: Fri, 29 Sep 2023 07:37:40 +1000 Subject: [PATCH] doc/architecture: edit "Replication" Edit "Replication" in the "Smart Daemons Enable Hyperscale" section of doc/architecture.rst. Signed-off-by: Zac Dover --- doc/architecture.rst | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/doc/architecture.rst b/doc/architecture.rst index a01c3e73d90..566b299389b 100644 --- a/doc/architecture.rst +++ b/doc/architecture.rst @@ -430,19 +430,20 @@ the greater cluster provides several benefits: weren't apparent in a light scrub. See `Data Scrubbing`_ for details on configuring scrubbing. -#. **Replication:** Like Ceph Clients, Ceph OSD Daemons use the CRUSH - algorithm, but the Ceph OSD Daemon uses it to compute where replicas of - objects should be stored (and for rebalancing). In a typical write scenario, - a client uses the CRUSH algorithm to compute where to store an object, maps - the object to a pool and placement group, then looks at the CRUSH map to - identify the primary OSD for the placement group. - - The client writes the object to the identified placement group in the - primary OSD. Then, the primary OSD with its own copy of the CRUSH map - identifies the secondary and tertiary OSDs for replication purposes, and - replicates the object to the appropriate placement groups in the secondary - and tertiary OSDs (as many OSDs as additional replicas), and responds to the - client once it has confirmed the object was stored successfully. +#. **Replication:** Data replication involves a collaboration between Ceph + Clients and Ceph OSD Daemons. Ceph OSD Daemons use the CRUSH algorithm to + determine the storage location of object replicas. Ceph clients use the + CRUSH algorithm to determine the storage location of an object, then the + object is mapped to a pool and to a placement group, and then the client + consults the CRUSH map to identify the placement group's primary OSD. + + After identifying the target placement group, the client writes the object + to the identified placement group's primary OSD. The primary OSD then + consults its own copy of the CRUSH map to identify secondary and tertiary + OSDS, replicates the object to the placement groups in those secondary and + tertiary OSDs, confirms that the object was stored successfully in the + secondary and tertiary OSDs, and reports to the client that the object + was stored successfully. .. ditaa:: @@ -469,9 +470,8 @@ the greater cluster provides several benefits: | | | | +---------------+ +---------------+ -With the ability to perform data replication, Ceph OSD Daemons relieve Ceph -clients from that duty, while ensuring high data availability and data safety. - +By performing this act of data replication, Ceph OSD Daemons relieve Ceph +clients of the burden of replicating data. Dynamic Cluster Management --------------------------