Did number of replicas effect ES memory utilization

[Eli_Revach]

Hi ,
We are facing Old GC's from time to time , i like to know if the amount of replica's has a direct impact on the ES memory utilization (looks to me that the answer is yes ) ?

bottom line , if it can increase chance for Old GC's ?

Thanks

[warkolm (Mark Walkom)]

Yes but it's more complicated than saying it's double the impact.

[Eli_Revach]

Thanks Mark .

Can you elaborate on it ?

I will be more specific , on my case .

Assuming my cluster is bigger (many node’s ) one , and we don’t use query routing , so basically each query runs on all cluster nodes.
ES , will used both replica && primary shards to scale my query’s , in term of memory utilization on a given none for specific primary shard , we may have memory utilization of replica shards from other nodes ( or ,and I don’t know if its doable case , memory utilization of replica from the same node , so the memory will include duplicate data set’s , for the primary + shard of the same data set’s )

Thanks

[warkolm (Mark Walkom)]

You are likely to "pay" twice the amount for maintaining shards as you have twice the number. But when you start looking at filter/query/agg caches it really depends on what gets queried where.