Dell POWEREDGE M1000E - Manual (Page 246)

214 Fabric OS Command Reference
53-1001764-02
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 by default enabled 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 due to the fact that
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. Since the ports 1/0-1/10 share the same chip, traffic in LS2 is affected whenever traffic for
LS1 on ports 1/0-5 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 LS 2 is not affected.
Notes You cannot enable Lossless when XISL use is enabled, and you cannot enable XISL use while
Lossless is enabled. In either case, the operation terminates with an appropriate error message.
Use the configure command to disable XISL use.
Fabric OS v6.4.0 and later supports Lossless with both exchange-based and port-based routing
policies. Behavior depends on the kind of policy configured and concurrent IOD settings. Refer to
the Fabric OS Administrator's Guide for information on how to optimize your configuration. Refer to
the aptPolicy help page for more information on routing policies.