Performance of application placed in the same subnet Database subnet


Hello, I am wondering does placing application instances in the same subnet with Database subnet increase performance of database reads in anyway? In the physical world components placed in the same subnet communicate with layer 2 (Switches) only, so one overhead of routing is removed. But I am not sure how this applies to Amazon VPC.

Thank you. Amanuel

1 Answer

Yes, if your application servers are in the same subnet, they will not have to connect across availability zone and as such have better latency to the database. However understand that if your database experiences any infrastructure issue that causes a failover the database can be moved to another subnet in the db-subnet-group.

answered a year ago
  • Hi Phil, Thank you for the response. Just to avoid confusion let's take Availability Zone out of the question. The App instance and DB to be in the same or different Subnet (Both in the same AZ) would it make a difference in network performance?

    Thank you Amanuel

  • I see what you are asking. Different subnets in the same az should not have any performance penalty. Of course you can confirm this with ping testing.

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