Proper bucket sizing

I have read through the cluster sizing docs, but I am still unclear on sizing the CB bucket properly.

Let’s say that each of my nodes will be allowed to use 65% of the system’s RAM for Couchbase. Each node has 4GB of RAM (this is hypothetical).

Total System RAM in MB per node: 4GB x 1024 = 4096
65% of system RAM allocated to Couchbase per node: 4096 * .65 = 2662
65% of Couchbase RAM allocated to data service per node: 2662 * .65 = 1731
35% of Couchbase RAM allocated to index service per node: 2662 * .35 = 932

This results in:

Data Service RAM: 1.731 GB
Index Service RAM: .932 GB
OS RAM: 1.433 GB

If I only have one bucket, is it OK to allocate the entire data service RAM to that single bucket? Or will that starve the data service somehow? What is the best practice for allocating RAM to buckets?

@patrick.kramer can you follow this doc page

Hi @patrick.kramer , if you have only one bucket and if you allocate entire data service RAM to that bucket, it should be fine. But keep in mind you will not have space to create another bucket later without deleting this one.

More information on sizing guidelines can be found here :


Can you not adjust the existing RAM quota for a bucket?? I thought that was possible, you’d just be ejecting keys/values from the cache.