From 0336e012ee4db92bb183aa25ed4e2e1998f04d2f Mon Sep 17 00:00:00 2001 From: Adam Locke Date: Tue, 25 May 2021 14:23:58 -0400 Subject: [PATCH] [DOCS] Update bi-directional CCR note (#72266) * [DOCS] Update bi-directional CCR note * Integrating note with a new sub-section * Add "particularly" --- docs/reference/ccr/index.asciidoc | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/docs/reference/ccr/index.asciidoc b/docs/reference/ccr/index.asciidoc index c8830baa78be..ddb9a7411da8 100644 --- a/docs/reference/ccr/index.asciidoc +++ b/docs/reference/ccr/index.asciidoc @@ -118,7 +118,7 @@ comes online, replication resumes between the clusters. image::images/ccr-arch-bi-directional.png[Bi-directional configuration where each cluster contains both a leader index and follower indices] -NOTE: This configuration is useful for index-only workloads, where no updates +This configuration is particularly useful for index-only workloads, where no updates to document values occur. In this configuration, documents indexed by {es} are immutable. Clients are located in each datacenter alongside the {es} cluster, and do not communicate with clusters in different datacenters. @@ -189,6 +189,18 @@ failure), the follower shard enters into a retry loop. Otherwise, the follower shard pauses <>. +[discrete] +[[ccr-update-leader-index]] +==== Processing updates +You can't manually modify a follower index's mappings or aliases. To make +changes, you must update the leader index. Because they are read-only, follower +indices reject writes in all configurations. + +For example, you index a document named `doc_1` in Datacenter A, which +replicates to Datacenter B. If a client connects to Datacenter B and attempts +to update `doc_1`, the request fails. To update `doc_1`, the client must +connect to Datacenter A and update the document in the leader index. + When a follower shard receives operations from the leader shard, it places those operations in a write buffer. The follower shard submits bulk write requests using operations from the write buffer. If the write buffer exceeds @@ -214,8 +226,6 @@ h| Update type h| Automatic h| As needed For example, changing the number of replicas on the leader index is not replicated by the follower index, so that setting might not be retrieved. -NOTE: You cannot manually modify a follower index's mappings or aliases. - If you apply a non-dynamic settings change to the leader index that is needed by the follower index, the follower index closes itself, applies the settings update, and then re-opens itself. The follower index is unavailable