Notice

This document is for a development version of Ceph.

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.

  • 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.

Brought to you by the Ceph Foundation

The Ceph Documentation is a community resource funded and hosted by the non-profit Ceph Foundation. If you would like to support this and our other efforts, please consider joining now.