From: Zac Dover Date: Fri, 5 Apr 2024 06:43:47 +0000 (+1000) Subject: doc/dev: refine "Concepts" 3 of 3 X-Git-Tag: v18.2.4~59^2 X-Git-Url: http://git.apps.os.sepia.ceph.com/?a=commitdiff_plain;h=29efccc02da8c2fb1f2f47e602d7eb5dbb68c4f0;p=ceph.git doc/dev: refine "Concepts" 3 of 3 Refine the third third of the entries in the section "Concepts" in doc/dev/peering.rst. Signed-off-by: Zac Dover (cherry picked from commit 512e2dc9d52fdd14dfdd87ccd141e535d3098fb7) --- diff --git a/doc/dev/peering.rst b/doc/dev/peering.rst index 6c38791382a80..29df2349ded3e 100644 --- a/doc/dev/peering.rst +++ b/doc/dev/peering.rst @@ -77,24 +77,22 @@ Concepts kept track of on an ```` basis. *Authoritative History* - a complete, and fully ordered set of operations that, if - performed, would bring an OSD's copy of a Placement Group - up to date. + a complete and fully-ordered set of operations that bring an OSD's copy of a + Placement Group up to date. *epoch* - a (monotonically increasing) OSD map version number + a (monotonically increasing) OSD map version number. *last epoch start* - the last epoch at which all nodes in the *acting set* - for a particular placement group agreed on an - *authoritative history*. At this point, *peering* is - deemed to have been successful. + the last epoch at which all nodes in the *acting set* for a given placement + group agreed on an *authoritative history*. At the start of the last epoch, + *peering* is deemed to have been successful. *up_thru* before a primary can successfully complete the *peering* process, it must inform a monitor that is alive through the current OSD map epoch by having the monitor set its *up_thru* in the osd - map. This helps peering ignore previous *acting sets* for which + map. This helps peering ignore previous *acting sets* for which peering never completed after certain sequences of failures, such as the second interval below: @@ -104,10 +102,9 @@ Concepts - *acting set* = [B] (B restarts, A does not) *last epoch clean* - the last epoch at which all nodes in the *acting set* - for a particular placement group were completely - up to date (both PG logs and object contents). - At this point, *recovery* is deemed to have been + the last epoch at which all nodes in the *acting set* for a given placement + group were completely up to date (this includes both the PG's PG logs and + the PG's object contents). At this point, *recovery* is deemed to have been completed. Description of the Peering Process