# Unexpected shard allocation with 0 replica indexes **URL:** \ **Category:** Elasticsearch\ **Created:** [February 22, 2015, 7:46pm UTC](https://discuss.elastic.co/t/unexpected-shard-allocation-with-0-replica-indexes/22317 "2015-02-22T19:46:20Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Todd\_Nine](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/todd_nine/32/778_2.png) [@Todd\_Nine](https://discuss.elastic.co/u/Todd_Nine)\ **Post date:** [February 22, 2015, 7:46pm UTC](https://discuss.elastic.co/t/unexpected-shard-allocation-with-0-replica-indexes/22317/1 "2015-02-22T19:46:20Z")
Hi All, We have several indexes in our ES cluster. ES is not our canonical system record, we use it only for searching. Some of our applications have very high write throughput, so for these we allocate a singular primary shard for each of our nodes. For example, we have 6 nodes, and we create our index with 6 shards and 0 replicas. I would expect ES to balance primary shards per node in the index. However, it will load as many as 3 primaries on a single node, and some nodes will have no shards. While each node does appear to have the same number of primaries, not all our indexes have equal write throughput, therefore, I want the primary (and only) shards evenly distributed per index. During heavy writes, we experience slowness because our shards are not evenly distributed across our nodes. Currently we're getting around this by manually moving shards, but this seems to be something ES should do automatically. We're running version 1.4.3 with default allocation parameter. Is this a bug? Thanks, Todd -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**Author:** ![warkolm](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/warkolm/32/39224_2.png) [@warkolm](https://discuss.elastic.co/u/warkolm)\ **Post date:** [February 22, 2015, 10:24pm UTC](https://discuss.elastic.co/t/unexpected-shard-allocation-with-0-replica-indexes/22317/2 "2015-02-22T22:24:55Z")
It's not a bug, ES allocates based on higher level primary shard count and doesn't take into account what index a shard may belong to, this is where allocation awareness and routing comes into play. Take a look at > **[Elasticsearch Platform — Find real-time answers at scale](https://www.elastic.co)** > > Power insights and outcomes with the Elasticsearch Platform and AI. See into your data and find answers that matter with enterprise solutions designed to help you build, observe, and protect. Try Elasticsearch free today. On 23 February 2015 at 06:46, Todd Nine [tnine@apigee.com](mailto:tnine@apigee.com) wrote: > Hi All, > We have several indexes in our ES cluster. ES is not our canonical > system record, we use it only for searching. > > Some of our applications have very high write throughput, so for these we > allocate a singular primary shard for each of our nodes. For example, we > have 6 nodes, and we create our index with 6 shards and 0 replicas. I > would expect ES to balance primary shards per node in the index. However, > it will load as many as 3 primaries on a single node, and some nodes will > have no shards. While each node does appear to have the same number of > primaries, not all our indexes have equal write throughput, therefore, I > want the primary (and only) shards evenly distributed per index. > > During heavy writes, we experience slowness because our shards are not > evenly distributed across our nodes. Currently we're getting around this > by manually moving shards, but this seems to be something ES should do > automatically. We're running version 1.4.3 with default allocation > parameter. Is this a bug? > > Thanks, > Todd > > -- > You received this message because you are subscribed to the Google Groups > "elasticsearch" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). > To view this discussion on the web visit > [https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com) > [https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com?utm\_medium=email&utm\_source=footer](https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com?utm_medium=email&utm_source=footer) > . > For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/CAEYi1X8Ue\_1SYTud9HZdC5aGHNOUJVA%2Bq8PT8LrQrzm7GaOZ7Q%40mail.gmail.com](https://groups.google.com/d/msgid/elasticsearch/CAEYi1X8Ue_1SYTud9HZdC5aGHNOUJVA%2Bq8PT8LrQrzm7GaOZ7Q%40mail.gmail.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**Author:** ![Todd\_Nine](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/todd_nine/32/778_2.png) [@Todd\_Nine](https://discuss.elastic.co/u/Todd_Nine)\ **Post date:** [February 23, 2015, 4:00pm UTC](https://discuss.elastic.co/t/unexpected-shard-allocation-with-0-replica-indexes/22317/3 "2015-02-23T16:00:15Z")
Thanks Mark, I've looked at these, as well as these configuration parameters. > **[Elasticsearch Platform — Find real-time answers at scale](https://www.elastic.co)** > > Power insights and outcomes with the Elasticsearch Platform and AI. See into your data and find answers that matter with enterprise solutions designed to help you build, observe, and protect. Try Elasticsearch free today. However, I've not been able to find a configuration that actually accomplishes what we're looking for. We're using the aws plugin as well, which doesn't seem to help any with our shard allocation. It does however, ensure we have replica's in other zones, which is obviously helpful for redundancy. Are there any known settings, either with allocation-awareness or cluster settings that will accomplish the behavior I'm looking for? Otherwise, we'll have to write client API to move the shards after index allocation to ensure we get our even load. Thanks, Todd On Sunday, February 22, 2015 at 3:25:28 PM UTC-7, Mark Walkom wrote: > It's not a bug, ES allocates based on higher level primary shard count and > doesn't take into account what index a shard may belong to, this is where > allocation awareness and routing comes into play. > > Take a look at > [Elasticsearch Platform — Find real-time answers at scale | Elastic](http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/modules-cluster.html#allocation-awareness) > > On 23 February 2015 at 06:46, Todd Nine \<[tn...@apigee.com](mailto:tn...@apigee.com) \\> > wrote: > > > Hi All, > > We have several indexes in our ES cluster. ES is not our canonical > > system record, we use it only for searching. > > > > Some of our applications have very high write throughput, so for these we > > allocate a singular primary shard for each of our nodes. For example, we > > have 6 nodes, and we create our index with 6 shards and 0 replicas. I > > would expect ES to balance primary shards per node in the index. However, > > it will load as many as 3 primaries on a single node, and some nodes will > > have no shards. While each node does appear to have the same number of > > primaries, not all our indexes have equal write throughput, therefore, I > > want the primary (and only) shards evenly distributed per index. > > > > During heavy writes, we experience slowness because our shards are not > > evenly distributed across our nodes. Currently we're getting around this > > by manually moving shards, but this seems to be something ES should do > > automatically. We're running version 1.4.3 with default allocation > > parameter. Is this a bug? > > > > Thanks, > > Todd > > > > -- > > You received this message because you are subscribed to the Google Groups > > "elasticsearch" group. > > To unsubscribe from this group and stop receiving emails from it, send an > > email to [elasticsearc...@googlegroups.com](mailto:elasticsearc...@googlegroups.com) \. > > To view this discussion on the web visit > > [https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com) > > [https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com?utm\_medium=email&utm\_source=footer](https://groups.google.com/d/msgid/elasticsearch/5cc33cd3-f7f6-4174-b815-cadc858c0b97%40googlegroups.com?utm_medium=email&utm_source=footer) > > . > > For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). -- You received this message because you are subscribed to the Google Groups "elasticsearch" group. To unsubscribe from this group and stop receiving emails from it, send an email to [elasticsearch+unsubscribe@googlegroups.com](mailto:elasticsearch+unsubscribe@googlegroups.com). To view this discussion on the web visit [https://groups.google.com/d/msgid/elasticsearch/8a6b76c7-87f0-4a2f-a08f-db9a6fb871f1%40googlegroups.com](https://groups.google.com/d/msgid/elasticsearch/8a6b76c7-87f0-4a2f-a08f-db9a6fb871f1%40googlegroups.com). For more options, visit [https://groups.google.com/d/optout](https://groups.google.com/d/optout). ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 12:30am UTC](https://discuss.elastic.co/t/unexpected-shard-allocation-with-0-replica-indexes/22317/4 "2017-07-06T00:30:47Z")