Fabric OS Command Reference
Fabric OS Command Reference
Fabric OS 7.0.1
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Fabric OS Commands : dlsSet

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:
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:
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.
Lossless is supported 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.
The Lossless feature is not supported on GbE ports and FCoE. On unsupported platforms, this command exits with an appropriate message.
The execution of this command is subject to Virtual Fabric or Admin Domain restrictions that may be in place. Refer to Chapter 1, "Using Fabric OS Commands" and Appendix A, "Command Availability" for details.
Operands
--enable -lossless
Enables the Lossless feature. Frame loss is reduced while the path is rerouted. If DLS is set on the switch, this command adds the Lossless feature to the existing DLS legacy mode. If DLS is not set on the switch, this command enables both DLS and the Lossless feature. The Lossless feature is disabled by default.
--disable -lossless
Disables the previously enabled Lossless feature. Execution of this command is equivalent to the legacy dlsSet command. Dynamic load balancing is enforced but not without frame loss. DLS (legacy mode) continues to be enabled after Lossless is disabled. Use dlsReset to disable DLS completely.
--help
Displays the command usage.
Examples
DLS configuration commands on a switch with an exchange-based policy:
switch:admin> aptpolicy
Current Policy: 3 0(ap)
 
3 0(ap) : Default Policy
1: Port Based Routing Policy
3: Exchange Based Routing Policy
0: AP Shared Link Policy
1: AP Dedicated Link Policy
 
switch:admin> dlsshow
 
DLS is set by default with current routing policy
 
DLS is set with Lossless enabled
 
switch:admin> dlsreset
 
DLS can not be changed with current routing policy
 
switch:admin> dlsset
 
DLS can not be changed with current routing policy
 
switch:admin> dlsset --enable -lossless
 
Lossless is set
 
switch:admin> dlsset --disable -lossless
 
Lossless is not set
 
switch:admin> dlssshow
 
DLS is set by default with current routing policy
DLS configuration commands on a switch with a port-based policy:
switch:admin> dlsshow
 
DLS is set by default with current routing policy
 
DLS is set with Lossless enabled
 
switch:admin> dlsreset
 
DLS is not set
 
switch:admin> dlsshow
 
DLS is not set
 
switch:admin> dlsset --enable -lossless
 
DLS and Lossless are set
 
switch:admin> dlsshow
 
DLS is set with Lossless enabled
 
switch:admin> dlsset
 
Lossless is set (unchanged)
 
switch:admin> dlsset --disable -lossless
 
Lossless is not set
 
switch:admin> dlsshow
 
DLS is not set
To attempt to enable Lossless while XISL use is enabled:
switch:admin> dlsset --enable -lossless
 
Lossless option cannot be enabled when XISL use is allowed.
Please disable the switch with 'switchdisable' and run \
'configure' to disallow XISL use before enabling Lossless.
See Also
aptPolicy, dlsReset, dlsShow, iodReset, iodSet, iodShow, uRouteShow, topologyShow

Fabric OS Commands : dlsSet