Brocade Fabric OS Command Reference (Supporting Fabric OS v7.3.0) - Manual (Page 279)

Fabric OS Command Reference 249
53-1003131-01
dlsSet
2
dlsSet
Enables Dynamic Load Sharing (DLS) without frame loss.
SYNOPSIS
dlsset
dlsset --enable -lossless
dlsset --enable -eportbal
dlsset --disable -lossless
dlsset --disable -eportbal
dlsset --rebalance
dlsset --rebalance -all
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.
Use this command to enable or disable the E_Port Balance Priority feature. Enabling E_Port balancing
causes the E_Port load to be even across all E_Ports to the same domain. E_Port balancing is disabled
by default.
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.