AWS RDS connection limits

AWS RDS max_connections limit variable is based on Instance type, so you can upgrade your RDS or make more replica.

The RDS types with max_connections limit:

  • t2.micro 66
  • t2.small 150
  • m3.medium 296
  • t2.medium 312
  • m3.large 609
  • t2.large 648
  • m4.large 648
  • m3.xlarge 1237
  • r3.large 1258
  • m4.xlarge 1320
  • m2.xlarge 1412
  • m3.2xlarge 2492
  • r3.xlarge 2540

Referring by max_connections at AWS RDS MySQL Instance Sizes in 2015

Update 2017-07

The current RDS MySQL max_connections setting is default by {DBInstanceClassMemory/12582880}, if you use t2.micro with 512MB RAM, the max_connections could be (512*1024*1024)/12582880 ~= 40, and so on.


Each Web server could have many connections to RDS, which depends on your SQL requests from Web server.

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