One node with high specs vs two nodes with medium specs. Performance expectation

[Prashant_Rana]

I want to know, what indexing performance (logs indexed per second) I can expect with the

single machine of 16 cores,16GB
vs
two-node setup of 8 cores and 16 GB RAM. (Two shards per index. Both nodes contain one shard)

Two node setup cannot match the performance I am getting with the single node with more cores. Is that expected?

[yago82]

@Prashant_Rana

Two node setup cannot match the performance I am getting with the single node with more cores. Is that expected?

Hi,

Indexing is a CPU-intensive operation. If the single node has more cores available for processing, it may be able to handle the indexing load more efficiently than multiple nodes with fewer cores.

Then, if your indices have multiple shards, a single powerful node might be able to handle the indexing into these shards more efficiently than if the shards are spread across multiple less powerful nodes.

Regards

[Christian_Dahlqvist]

Indexing performance is not necessarily limited by CPU and/or RAM. Storage performance can often be a limiting factor and limited network performance can also play a part if there are multiple nodes in the cluster.

When you index into a single node cluster you know that all the primary shards reside on that node and there is little overhead. If you instead index into a cluster it is likely that a lot of the data need to be sent between nodes for indexing as the primary shards may be spread out and indexed data alo need to be forwarded to replica shards. This adds overhead but can also increase resilience.

You did not specify how large the difference in indexing throughput was between your two tests so it is hard to tell whether this is expected or not. It would also be useful if you could provide information about the network capacity and storage used.