# Consistency across cluster

**URL:** <https://discuss.elastic.co/t/consistency-across-cluster/8516>\
**Category:** Elasticsearch\
**Created:** [July 25, 2012, 7:05pm UTC](https://discuss.elastic.co/t/consistency-across-cluster/8516 "2012-07-25T19:05:13Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Kinesh\_Satiya\_2](https://avatars.discourse-cdn.com/v4/letter/k/bb73d2/32.png) [@Kinesh\_Satiya\_2](https://discuss.elastic.co/u/Kinesh_Satiya_2)\
**Post date:** [July 25, 2012, 7:05pm UTC](https://discuss.elastic.co/t/consistency-across-cluster/8516/1 "2012-07-25T19:05:13Z")

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I have a cluster running which has 4 nodes. Each node has an EBS volume  
attached to it, where the node backs up all the indexes it has.

So,  
node1 =\> ebs 1  
node2 =\> ebs 2  
node3 =\> ebs 3  
node4 =\> ebs 4

Now I need to shut down node 4. Since the load is less on this cluster, I  
shut down one the node and have written a script to re spawn it when the  
load increases on the cluster or more memory is required.

So, in the case when the node4 is re-spawned, it will attach its ebs 4 and  
start loading all of these indexes stored in the shard.

Lets say some of the indexes which were initially with node 4 got updated  
after node 4 is down ( node 1 has a replicated copy and node 1 updates  
those indexes), then when node 4 is re-spawned, Will node 4 look for  
updates and then update the indexes in its shard? or will it read the shard  
and contain old indexes ( not updated) ?

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**Author:** ![simonw\_2](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/simonw_2/32/1130_2.png) [@simonw\_2](https://discuss.elastic.co/u/simonw_2)\
**Post date:** [July 25, 2012, 7:09pm UTC](https://discuss.elastic.co/t/consistency-across-cluster/8516/2 "2012-07-25T19:09:36Z")

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On Wednesday, July 25, 2012 9:05:13 PM UTC+2, Kinesh Satiya wrote:

> I have a cluster running which has 4 nodes. Each node has an EBS volume  
> attached to it, where the node backs up all the indexes it has.
> 
> So,  
> node1 =\> ebs 1  
> node2 =\> ebs 2  
> node3 =\> ebs 3  
> node4 =\> ebs 4
> 
> Now I need to shut down node 4. Since the load is less on this cluster, I  
> shut down one the node and have written a script to re spawn it when the  
> load increases on the cluster or more memory is required.
> 
> So, in the case when the node4 is re-spawned, it will attach its ebs 4 and  
> start loading all of these indexes stored in the shard.
> 
> Lets say some of the indexes which were initially with node 4 got updated  
> after node 4 is down ( node 1 has a replicated copy and node 1 updates  
> those indexes), then when node 4 is re-spawned, Will node 4 look for  
> updates and then update the indexes in its shard? or will it read the shard  
> and contain old indexes ( not updated) ?

if the node joins the cluster again ES will recover the index shards on  
that machine and bring them up-to-date. You can try that out and see how  
the cluster state changes. Just shut it down and index a couple of  
documents. Then bring it up again and shut down the other node holding the  
same shard. it should be in sync once recovery has finished. Make sure  
recovery is done before you stop another node.

simon

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**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, 3:19am UTC](https://discuss.elastic.co/t/consistency-across-cluster/8516/3 "2017-07-06T03:19:00Z")

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