From 9e8c4704a83bd18b950a25797923c092d0b075af Mon Sep 17 00:00:00 2001 From: David Turner Date: Mon, 30 Apr 2018 09:15:50 +0100 Subject: [PATCH 1/2] Improve allocation-disabling instructions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Clarify the “one minute” in the instructions to disable the shard allocation when doing maintenance to say that it is configurable. Add a note about making sure that no rebalancing occurs until the maintenance is complete. Relates #19739. --- .../upgrade/disable-shard-alloc.asciidoc | 22 ++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/docs/reference/upgrade/disable-shard-alloc.asciidoc b/docs/reference/upgrade/disable-shard-alloc.asciidoc index 107d20f1135ce..723d9151d838f 100644 --- a/docs/reference/upgrade/disable-shard-alloc.asciidoc +++ b/docs/reference/upgrade/disable-shard-alloc.asciidoc @@ -1,8 +1,10 @@ -When you shut down a node, the allocation process waits for one minute -before starting to replicate the shards on that node to other nodes -in the cluster, causing a lot of wasted I/O. You can avoid racing the clock -by disabling allocation before shutting down the node: +When you shut down a node, the allocation process waits for +`index.unassigned.node_left.delayed_timeout` (by default, one minute) before +starting to replicate the shards on that node to other nodes in the cluster, +which can involve a lot of I/O. Since the node is shortly going to be +restarted, this I/O is unnecessary. You can avoid racing the clock by disabling +allocation before shutting down the node: [source,js] -------------------------------------------------- @@ -14,4 +16,14 @@ PUT _cluster/settings } -------------------------------------------------- // CONSOLE -// TEST[skip:indexes don't assign] \ No newline at end of file +// TEST[skip:indexes don't assign] + +Additionally, the allocation process attempts to keep the shards balanced +across the cluster by performing rebalancing, moving shards between nodes. This +involves I/O that is also unnecessary if the shut-down node will shortly +return, so it is preferable for the cluster not to attempt to perform any +rebalancing until the maintenance is complete. This is the default behaviour, +but can be changed using the `cluster.routing.allocation.allow_rebalance` +setting. Make sure that this setting is unset, or set to the default value of +`indices_all_active`, before continuing. + From 30bee2781dc260f81bca9e6043c32faf98880a2c Mon Sep 17 00:00:00 2001 From: David Turner Date: Wed, 16 May 2018 12:03:44 +0100 Subject: [PATCH 2/2] Revert extra para --- docs/reference/upgrade/disable-shard-alloc.asciidoc | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/docs/reference/upgrade/disable-shard-alloc.asciidoc b/docs/reference/upgrade/disable-shard-alloc.asciidoc index 723d9151d838f..abd40336e9b08 100644 --- a/docs/reference/upgrade/disable-shard-alloc.asciidoc +++ b/docs/reference/upgrade/disable-shard-alloc.asciidoc @@ -16,14 +16,4 @@ PUT _cluster/settings } -------------------------------------------------- // CONSOLE -// TEST[skip:indexes don't assign] - -Additionally, the allocation process attempts to keep the shards balanced -across the cluster by performing rebalancing, moving shards between nodes. This -involves I/O that is also unnecessary if the shut-down node will shortly -return, so it is preferable for the cluster not to attempt to perform any -rebalancing until the maintenance is complete. This is the default behaviour, -but can be changed using the `cluster.routing.allocation.allow_rebalance` -setting. Make sure that this setting is unset, or set to the default value of -`indices_all_active`, before continuing. - +// TEST[skip:indexes don't assign] \ No newline at end of file