From 9f4a436babab13165a580d7a1a889d84958d566f Mon Sep 17 00:00:00 2001 From: Zac Dover Date: Thu, 28 Sep 2023 13:55:02 +1000 Subject: [PATCH] doc/architecture: edit "OSD Membership and Status" Edit "OSD Membership and Status" in the "Smart Daemons Enable Hyperscale" section of doc/architecture.rst. Co-authored-by: Anthony D'Atri Signed-off-by: Zac Dover (cherry picked from commit dbd85336b1aa3ef42cfc12495b3dc5142d4b8a28) --- doc/architecture.rst | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/doc/architecture.rst b/doc/architecture.rst index f1cb362c203..08ccc268fcd 100644 --- a/doc/architecture.rst +++ b/doc/architecture.rst @@ -403,20 +403,22 @@ the greater cluster provides several benefits: maintain sessions only when needed, and maintain those sessions with only particular Ceph OSD daemons, not with a centralized interface. -#. **OSD Membership and Status**: Ceph OSD Daemons join a cluster and report - on their status. At the lowest level, the Ceph OSD Daemon status is ``up`` - or ``down`` reflecting whether or not it is running and able to service - Ceph Client requests. If a Ceph OSD Daemon is ``down`` and ``in`` the Ceph - Storage Cluster, this status may indicate the failure of the Ceph OSD - Daemon. If a Ceph OSD Daemon is not running (e.g., it crashes), the Ceph OSD - Daemon cannot notify the Ceph Monitor that it is ``down``. The OSDs - periodically send messages to the Ceph Monitor (``MPGStats`` pre-luminous, - and a new ``MOSDBeacon`` in luminous). If the Ceph Monitor doesn't see that - message after a configurable period of time then it marks the OSD down. - This mechanism is a failsafe, however. Normally, Ceph OSD Daemons will - determine if a neighboring OSD is down and report it to the Ceph Monitors. - This assures that Ceph Monitors are lightweight processes. See `Monitoring - OSDs`_ and `Heartbeats`_ for additional details. +#. **OSD Membership and Status**: When Ceph OSD Daemons join a cluster, they + report their status. At the lowest level, the Ceph OSD Daemon status is + ``up`` or ``down``: this reflects whether the Ceph OSD daemon is running and + able to service Ceph Client requests. If a Ceph OSD Daemon is ``down`` and + ``in`` the Ceph Storage Cluster, this status may indicate the failure of the + Ceph OSD Daemon. If a Ceph OSD Daemon is not running because it has crashed, + the Ceph OSD Daemon cannot notify the Ceph Monitor that it is ``down``. The + OSDs periodically send messages to the Ceph Monitor (in releases prior to + Luminous, this was done by means of ``MPGStats``, and beginning with the + Luminous release, this has been done with ``MOSDBeacon``). If the Ceph + Monitors receive no such message after a configurable period of time, + then they mark the OSD ``down``. This mechanism is a failsafe, however. + Normally, Ceph OSD Daemons determine if a neighboring OSD is ``down`` and + report it to the Ceph Monitors. This contributes to making Ceph Monitors + lightweight processes. See `Monitoring OSDs`_ and `Heartbeats`_ for + additional details. #. **Data Scrubbing:** As part of maintaining data consistency and cleanliness, Ceph OSD Daemons can scrub objects. That is, Ceph OSD Daemons can compare -- 2.39.5