From 9993df8d5eb7a1b1ae1a714c4805d178faac14fa Mon Sep 17 00:00:00 2001 From: Ed Costello Date: Wed, 5 Sep 2012 10:35:19 -0400 Subject: [PATCH 1/2] DOCS-153 add note about all config servers needing to be up on initial setup also fix error (elided sentence) introduced in fc3b14f14d419628d25fd7fad401b996f5cb62f5 --- source/administration/sharding.txt | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/source/administration/sharding.txt b/source/administration/sharding.txt index 30a193987a2..d9cbb2c4202 100644 --- a/source/administration/sharding.txt +++ b/source/administration/sharding.txt @@ -59,6 +59,10 @@ more detail or use the following procedure as a quick starting point: :doc:`command line ` and :doc:`configuration file ` options are available for config server instances. + +.. note:: + + All config servers must be running when you first set up a shard cluster. #. Start a :program:`mongos` instance issuing the following command: @@ -889,8 +893,10 @@ For redundancy, all production :term:`shard clusters ` should deploy three config servers processes on three different machines. Do not use only a single config server for production deployments. -Consider deploying a single config server for testing. -immediately. The following process shows how to upgrade from one to +Consider deploying a single config server only for testing. +You should upgrade to three config servers immediately if you are +shifting to production. +The following process shows how to upgrade from one to three config servers. #. Shut down all existing MongoDB processes. This includes: From 64bdf6d805c9681e18568a45f441b767c2cdbb09 Mon Sep 17 00:00:00 2001 From: Ed Costello Date: Wed, 5 Sep 2012 10:53:28 -0400 Subject: [PATCH 2/2] DOCS-153 all config servers must be up to init cluster --- source/administration/sharding-architectures.txt | 4 ++++ source/core/sharding.txt | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/source/administration/sharding-architectures.txt b/source/administration/sharding-architectures.txt index 25ce5d66d11..577d2e08226 100644 --- a/source/administration/sharding-architectures.txt +++ b/source/administration/sharding-architectures.txt @@ -166,3 +166,7 @@ potential failure scenarios and available resolutions: splits `. Replace the config server as soon as possible. If all multiple config databases become unavailable, the cluster can become inoperable. + + .. note:: + + All config servers must be running when you first set up a shard cluster. diff --git a/source/core/sharding.txt b/source/core/sharding.txt index 762e0ec8e07..f7963bb8696 100644 --- a/source/core/sharding.txt +++ b/source/core/sharding.txt @@ -334,6 +334,10 @@ database. MongoDB only writes data to the config server to: - migrate a chunk between shards. +Additionally, all config servers must be available on initial setup +of a shard cluster, each :program:`mongos` instance must be able +to write to the ``config.version`` collection. + If one or two configuration instances become unavailable, the cluster's metadata becomes *read only*. It is still possible to read and write data from the shards, but no chunk migrations or splits will