Dell Brocade 6520 Command Reference Supporting Fabric OS v7.1.0 - Page 271

dlsSet 2 dlsSet Enables Dynamic Load Sharing (DLS) without frame loss. SYNOPSIS dlsset dlsset --enable -lossless dlsset --disable -lossless dlsset --help DESCRIPTION Use this command to enable or disable Dynamic Load Sharing (DLS) in the event of a fabric change, to configure DLS without frame loss, and to display the DLS configuration. Dynamic load sharing optimizes the utilization of the interswitch links (ISLs) by rebalancing the paths going over the ISLs whenever there is a fabric event that may result in a sub-optimal utilization of the ISL. Dynamic rebalancing can be triggered by any one of the following events: • A change in the fabric occurs. • A local E_Port (including trunk ports) goes up or down. • A local Fx_Port goes down. When used without operands, this command enables Dynamic Load Sharing on a switch (legacy DLS behavior). Frames may be lost during reroute operations. If the switch has an exchanged-based routing policy, DLS is enabled by default and this command fails with the following message: "DLS can not be changed with current routing policy." During the load sharing recomputation, existing routes may be moved to maintain optimal load balance. Frame loss is unavoidable when a port goes down. To prevent frames from being lost during this operation, you can enable DLS without frame loss by issuing this command with the --enable -lossless option. Dynamic load sharing without frame loss is supported in logical fabrics and is configured per logical switch. However, there is a potential impact on other logical switches because they share the same hardware. Chassis permissions are required to configure DLS in a logical fabric environment. For example, assume a chassis is partitioned as follows: logical switch LS1 consists of ports 1/0-1/5, and logical switch LS2 consists of ports 1/6-1/10. Lossless is enabled on logical switch LS1. Because the ports 1/0-1/10 share the same chip, traffic in LS2 is affected whenever traffic for LS1 on ports 1/0-1/5 is rebalanced. The impact on LS2 depends on the configuration on LS2: • If the Lossless feature is enabled on LS1, traffic pauses and resumes without frame loss on both switches at the same time. • If the Lossless feature is disabled on LS1, traffic on LS2 is not affected. Fabric OS Command Reference 243 53-1002746-01