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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-21 11:54:28 +0000 |
commit | e6918187568dbd01842d8d1d2c808ce16a894239 (patch) | |
tree | 64f88b554b444a49f656b6c656111a145cbbaa28 /doc/dev/osd_internals/pg.rst | |
parent | Initial commit. (diff) | |
download | ceph-upstream/18.2.2.tar.xz ceph-upstream/18.2.2.zip |
Adding upstream version 18.2.2.upstream/18.2.2
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | doc/dev/osd_internals/pg.rst | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/doc/dev/osd_internals/pg.rst b/doc/dev/osd_internals/pg.rst new file mode 100644 index 000000000..397d4ab5d --- /dev/null +++ b/doc/dev/osd_internals/pg.rst @@ -0,0 +1,31 @@ +==== +PG +==== + +Concepts +-------- + +*Peering Interval* + See PG::start_peering_interval. + See PG::acting_up_affected + See PG::PeeringState::Reset + + A peering interval is a maximal set of contiguous map epochs in which the + up and acting sets did not change. PG::PeeringMachine represents a + transition from one interval to another as passing through + PeeringState::Reset. On PG::PeeringState::AdvMap PG::acting_up_affected can + cause the pg to transition to Reset. + + +Peering Details and Gotchas +--------------------------- +For an overview of peering, see `Peering <../../peering>`_. + + * PG::flushed defaults to false and is set to false in + PG::start_peering_interval. Upon transitioning to PG::PeeringState::Started + we send a transaction through the pg op sequencer which, upon complete, + sends a FlushedEvt which sets flushed to true. The primary cannot go + active until this happens (See PG::PeeringState::WaitFlushedPeering). + Replicas can go active but cannot serve ops (writes or reads). + This is necessary because we cannot read our ondisk state until unstable + transactions from the previous interval have cleared. |