Extend cluster, new data nodes, identical disk space?

Hello,

I have a cluster with 4 data nodes, each with a storage of 4 To dedicated to the ES datas.

Can i add 2 more data nodes, but only with 2 To of disk dedicated to the ES datas ?

I don’t know if ES will handle this nicely.

Elasticsearch 7.10.

Thanks.

Yes, it is possible.

but you need to check the total index size and your sharing strategy.

Because once the new nodes are added the shard relocation will happen and there should be enough space available in the new nodes.

The best practice is to use all data nodes with similar infra. (CPU,RAM,Disk etc).

Welcome to our community! :smiley:

What is "To"?

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might be a typo for tb , thats what i thought!

Some languages (e.g. French) call bytes "octets", and thus they abbreviate it to "o" instead of "b".

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by enough space, you mean «in the cluster globally» ?

How is the space managed ? Will ES allocate no more than % percent by node ?
or relocation is based only on the number of shards per node ?

Shard allocation is the process of allocating shards to nodes. This can happen during initial recovery, replica allocation, rebalancing, or when nodes are added or removed.

One of the main roles of the master is to decide which shards to allocate to which nodes, and when to move shards between nodes in order to rebalance the cluster.

There are a number of settings available to control the shard allocation process:

Besides these, there are a few other miscellaneous cluster-level settings.

Refer here for more details: Cluster-level shard allocation and routing settings | Elasticsearch Guide [7.15] | Elastic

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Thank you for this full answer, i will read all theses links.