Load balancing Dell EMC ECS

How to load balance Dell EMC ECS

Persistence (Aka Server Affinity)

Persistence is only recommended for NFS connections when load balancing a Dell EMC ECS deployment. This is due to the fact that caching occurs on the ECS servers when the NFS protocol is used. To maximize efficiency, a given NFS client should continue connecting to the same ECS server, so as to continue re-using the established cache.

Virtual Service (VIP) Requirements

To provide load balancing and HA for Dell EMC ECS, the following VIPs are usually required:

• S3 (for object access via the S3 protocol)
• Atmos (for object access via the Atmos protocol)
• Swift (for object access via the Swift protocol)
• NFS (for providing highly available NFS services)

Optionally, additional VIPs may be required as follows:

• ECS Combined Service (for scenario 2, where only a single IP address is client-facing)
• TLS/SSL termination service (for scenario 2, where HTTPS traffic must be decrypted for inspection)

Port Requirements

The following table shows the ports that are load balanced:

TLS/SSL Termination

Terminating TLS/SSL connections on the load balancer is not recommended, due to the significant computational overhead, this introduces on the load balancer. Termination and decryption should continue to occur at the ECS servers, which are designed and best placed to perform this function. It may be necessary to terminate and decrypt traffic at the load balancer, so that it may then be read as plaintext and sorted. This is required if sorting incoming traffic by protocol is not possible by using different ports or IP addresses.

Health Checks

S3, Atmos, and Swift Virtual Services

The S3 and Swift virtual services use protocol-specific health checks to query the readiness of a given ECS server to accept connections for those protocols. The Atmos virtual service uses a standard ‘connect to port’ check, which examines whether the Atmos port is open on a given ECS server to determine whether the server is ready to accept connections using the Atmos protocol.

NFS Virtual Service

The NFS virtual service uses a standard ‘connect to port’ check by default, which examines whether the NFS port (2049) is open on a given ECS server to determine whether the server is ready to accept NFS connections. It is possible to configure a custom health check for the NFS service, which will check the availability of all three ports related to NFS operation (111, 2049, and 10000) on the real servers. Only if all three ports are available will a real server be considered ‘healthy’ and ready to accept NFS connections.

There are two deployment scenarios when using Loadbalancer.org appliances as part of a Dell EMC ECS deployment.

Scenario 1 – Virtual Services for each protocol

Note: VIPs = Virtual IP Addresses

Scenario 2 – Single Client-Facing Virtual Service

Note: VIPs = Virtual IP Addresses