From 81a1355db417004766f4f395a3123257b40d0bdc Mon Sep 17 00:00:00 2001 From: Naarcha-AWS <97990722+Naarcha-AWS@users.noreply.github.com> Date: Thu, 19 Sep 2024 07:35:05 -0500 Subject: [PATCH] Update index.md (#8340) Signed-off-by: Naarcha-AWS <97990722+Naarcha-AWS@users.noreply.github.com> --- _tuning-your-cluster/index.md | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/_tuning-your-cluster/index.md b/_tuning-your-cluster/index.md index ca9a147ec2..fa0973395f 100644 --- a/_tuning-your-cluster/index.md +++ b/_tuning-your-cluster/index.md @@ -198,10 +198,11 @@ To further fine-tune your shard allocation, you can set custom node attributes f You can set custom node attributes on OpenSearch nodes to be used for shard allocation awareness. For example, you can set the `zone` attribute on each node to represent the zone in which the node is located. You can also use the `zone` attribute to ensure that the primary shard and its replica shards are allocated in a balanced manner across available, distinct zones. In this scenario, maximum shard copies per zone would equal `ceil (number_of_shard_copies/number_of_distinct_zones)`. -OpenSearch, by default, allocates shard copies of a single shard across different nodes. When only 1 zone is available, such as after a zone failure, OpenSearch allocates replica shards to the only remaining zone i.e. it considers only available zones (attribute values) for calculating maximum allowed shard copies per zone. +OpenSearch, by default, allocates shard copies of a single shard across different nodes. When only 1 zone is available, such as after a zone failure, OpenSearch allocates replica shards to the only remaining zone---it considers only available zones (attribute values) when calculating the maximum number of allowed shard copies per zone. + For example, if your index has a total of 5 shard copies (1 primary and 4 replicas) and nodes in 3 distinct zones, then OpenSearch will perform the following to allocate all 5 shard copies: -- Allocate not more than 2 shards per zone, which will require at least 2 nodes in 2 zones. +- Allocate no more than 2 shards per zone, which will require at least 2 nodes in 2 zones. - Allocate the last shard in the third zone, with at least 1 node needed in the third zone. Alternatively, if you have 3 nodes in the first zone and 1 node in each remaining zone, then OpenSearch will allocate: