Azure Mysql NDB Cluster

[Nugroho Raharjo]

I've problem with my Mysql NDB Cluster on Azure VM. I have 2 API Server and 1 Management Server on the same server with first API Server, and 2 Node of data. All servers are using Debian 9 and the version of Mysql Cluster is 7.4.7

I've already setup it on azure with same VNet and using E4s_v3 Plans for both API Server (4 Core CPU and 32GB Memory) and E8s_v3 Plans for both Data Server (8 Core CPU and 64GB Memory)

The problem is:

If I only use 1 API and 1 Data, the query takes 3.xx seconds, but if i run with 1 API and 2 Data, it will take 8.xx - 10.xx seconds
If I query small data it's running fast, but if the table has many records the query is too slow.

Can anyone help me solving my problem? I'm confused about what's wrong with my cluster. In general it can run fast.

Thanks