Thanos Receiver - why does it need consistent hashing?

[oronsh]

Hello,
I'm trying to understand why thanos receive uses a hashring as its load balancer rather than a simple round robin?
Thanks a lot!

[bill3tt]

Hey @oronsh - with a simple round robin load balancer you would end up writing a subset of samples for every metric to every Thanos receive instance! This would impose huge overheads on the index & memory requirements of each receive instance.

We use a hashring so that we can achieve consistent hashing of the data. This means that if an element is added or removed from the hashring, the minimal number of elements possible are re-assigned across receive instances.

Hope that makes sense!