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Posts: 1
Registered: ‎04-28-2013

Best Way to Remove ISL from Edge Switches


Hello,

I want to reduce the number of ISL connections I have in my fabric going out to my edge switches. Currently I have anywhere from 4-8 connections to these switches and I am utilizing around 4-10% of that bandwidth.

My first attempt was to disable the ports from the edge switch side and then disconnect the ports. In some cases this was not as seemless as I would have expected to my multi-pathed host behind the edge switches.

Is there a better process I should utilize for removing extra ISL connections that will be seemless to all hosts that are connected to the edge?

Thanks in advance.

Contributor
Posts: 66
Registered: ‎03-31-2013

Re: Best Way to Remove ISL from Edge Switches

It is a normal practise to disable the ports and then to disconnect the cables.

But do it when there is less traffic flow through the ISL.

I dont think so it will create an issue.

Did you face any issue during this process

Valued Contributor
Posts: 539
Registered: ‎03-20-2011

Re: Best Way to Remove ISL from Edge Switches

if you are at fos 7+ you can use portdecom command

Super Contributor
Posts: 445
Registered: ‎04-08-2009

Re: Best Way to Remove ISL from Edge Switches

Just to add on to what alexey.stepanov already provided...

Link to port decommissioning in the FOS Admin Guide:  http://www.brocade.com/downloads/documents/html_product_manuals/FOS_AG_710/wwhelp/wwhimpl/js/html/wwhelp.htm#href=advCfgTasks.09.03.html

Port decommissioning

Fabric OS 7.0.0 and later provides an automated mechanism to remove an E_Port or E_Port trunk port from use. This feature identifies the target port and communicates the intention to decommission the port to those systems within the fabric affected by the action. Each affected system can agree or disagree with the action, and these responses are automatically collected before a port is decommissioned.

NOTE: All members of a trunk group must have an equal link cost value in order for any of the members to be decommissioned. If any member of a trunk group does not have an equal cost, requests to decommission a trunk member will fail and an error reminding the caller of this requirement is produced.

The following restrictions apply to port decommissioning:

  • The local switch and the remote switch on the other end of the E_Port must both be running Fabric OS 7.0.0 or later.
  • Port decommissioning is not supported on links configured for encryption or compression.
  • Port decommissioning is not supported on ports with DWDM, CWDM, or TDM.
  • Port decommissioning requires that the lossless feature is enabled on both the local switch and the remote switch.
  • Use the portDecom port command to begin the decommission process.
Regards,

Mike Eversole
Brocade Community Manager
New Contributor
Posts: 3
Registered: ‎08-22-2011

Re: Best Way to Remove ISL from Edge Switches

I always like to bleed traffic off the ports by raising the linkcost on the ISL. That gives hosts a chance to renegotiate their paths prior to downing the link.

Occasional Contributor
Posts: 13
Registered: ‎06-16-2014

Re: Best Way to Remove ISL from Edge Switches

quote:

 

  • Port decommissioning requires that the lossless feature is enabled on both the local switch and the remote switch.

 


What exactly is this "lossless" feature and how can it be enabled/disabled?
The portdecommission command doesn't work on our FOS 7 switches, we get an error saying that the lossless feature must be enabled to use this command.

To disable an ISL with minimalimpact, we usually elevate the link cost (linkcost command) until no more trafic is going over it before disabling the ports on both ends, but I'd like to use this new portdecommission command instead.

 

Occasional Contributor
Posts: 19
Registered: ‎09-23-2011

Re: Best Way to Remove ISL from Edge Switches

dlsSet

 
Enables Dynamic Load Sharing (DLS) without frame loss.

 

dlsset
dlsset --enable -lossless

dlsset --enable -eportbal

dlsset --enable -twohop

dlsset --disable -lossless

dlsset --disable -eportbal

dlsset --disable -twohop

dlsset --rebalance
dlsset --rebalance -all

dlsset --help

 

Use this command to enable or disable lossless 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 is enabled and cannot be changed with the 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.

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