I'm new to elasticsearch and try to understand the basics. I try to
calculate the correct number of nodes for a specific index size. Let's
start with an example:
The index size is 100 GB, number of replicas=2, number of shards does
not matter (I guess), so for optimal performance, there should be
100GB + 2x100GB = 300GB in memory.
If my servers have 32GB of ram, I would need 10 of those = rougly 30GB
for elasticsearch and 2GB for the operating system. Is this correct?
Half a year later, the index grows to 200GB, my options are either
a) to add another 10 servers with 32GB of ram or
b) replace the old 32GB-ram servers with 10 new 64GB ram servers.
From what I've read so far I can't mix servers with different speeds
and different memory sizes, the slowest one is always the bottleneck.