Hi Shawn,thanks for your reply,
The following is my cluster status. The maxShardsPerNode configuration is 1,
but I created a collection search1. Both replicas of shard1 are assigned to
192.168.52.164:8280_solr this node.
Could this be a bug?
{
"responseHeader":{
"status":0,
"QTime":2},
"cluster":{
"collections":{
"search1":{
"pullReplicas":"0",
"replicationFactor":"2",
"shards":{
"shard1":{
"range":"80000000-ffffffff",
"state":"active",
"replicas":{
"core_node7":{
"core":"search1_shard1_replica_n1",
"base_url":"http://192.168.52.164:8280/solr";,
"node_name":"192.168.52.164:8280_solr",
"state":"active",
"type":"NRT"},
"core_node8":{
"core":"search1_shard1_replica_n2",
"base_url":"http://192.168.52.164:8280/solr";,
"node_name":"192.168.52.164:8280_solr",
"state":"active",
"type":"NRT",
"leader":"true"}}},
"shard2":{
"range":"0-7fffffff",
"state":"active",
"replicas":{
"core_node5":{
"core":"search1_shard2_replica_n3",
"base_url":"http://192.168.52.164:8480/solr";,
"node_name":"192.168.52.164:8480_solr",
"state":"active",
"type":"NRT",
"leader":"true"},
"core_node6":{
"core":"search1_shard2_replica_n4",
"base_url":"http://192.168.52.164:8580/solr";,
"node_name":"192.168.52.164:8580_solr",
"state":"active",
"type":"NRT"}}}},
"router":{"name":"compositeId"},
"maxShardsPerNode":"1",
"autoAddReplicas":"false",
"nrtReplicas":"2",
"tlogReplicas":"0",
"znodeVersion":9,
"configName":"search"}},
"properties":{"legacyCloud":"true"},
"live_nodes":["192.168.52.164:8280_solr",
"192.168.52.164:8580_solr",
"192.168.52.164:8180_solr",
"192.168.52.164:8380_solr",
"192.168.52.164:8480_solr"]}}
From: Shawn Heisey
Date: 2022-01-17 06:08
To: users
Subject: Re: Consult the meaning of maxShardsPerNode
On 1/16/2022 1:07 AM, [email protected] wrote:
> The following is a part of my cluster status
> I configured maxShardsPerNode to 1,but I can still create a collection
> with 2 shards and 2 replicas each shard on a node(From the web gui).
<snip>
> Now I'm confused about the meaning of maxShardsPerNode.
A setting of maxShardsPerNode=1 means that the collection can only place
one of its shards on each node. In actuality it's shard replicas that
it is referring to. A 3 shard collection with 2 replicas has a total of
6 shard replicas.
With 5 total nodes, you should probably use maxShardsPerNode=2 when you
create the collection.
I did this on a cloud example created with 4 nodes. I wanted to try it
with 5, but the example only allows up to 4. This is the distribution I
ended up with:
https://www.dropbox.com/s/f41599jqlano4r3/collection_test3x2.png?dl=0
Based on this, I think that if you did maxShardsPerNode=2, 3 shards, and
2 replicas on a 5-node cloud, you would end up with 1 shard replica on 4
of the nodes, and 2 shard replicas on the fifth.
Thanks,
Shawn
