• SQL Server is using high Memory / CPU resources constantly.
• Load balancing is uneven across the EC2 instances
• Poor OS performance due to high resource utilisation
The issue could be either with NLB configuration or with SQL + EC2 instance configuration.
Verify the configuration, if you have manually configured SQL server on the OS. If the image was pre-loaded with the instance - then the configuration should remain constant across all the servers
• Logon to the servers.
• Open SQL Server Configuration Manager
• Under SQL Native Client Configuration – verify the configuration is same across all the nodes
• Under SQL Server Network Configuration – verify correct protocols for MSSQLServers are enabled.
Verify Processor and Memory configuration for SQL services
## This defines amount of resources allocated to the DB. If the min and max are equal, the DB will never flush the resources - causing performance issues
Cross-Zone Load Balancing : When the EC2 instances are unevenly distributed amongs multiple availability zone - make sure this option is enabled.
For Linux clients using dnsmasq for DNS caching, run one of the following commands
For Linux clients using BIND for DNS caching, run one of the following commands:
For Windows clients, run the following command:
If you use duration-based session stickiness, configure an appropriate cookie expiration time for your specific use case. For more information, see:
If you set session stickiness from individual applications, use session cookies instead of persistent cookies where possible. For more information, see Application-Controlled Session Stickiness (Classic Load Balancers).