Fibre Channel (SAN)

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New Member
Posts: 1
Registered: ‎09-08-2014

Fabric OS v.6.4.3b: long distance: why should I turn off DLS?

Dear all,

 

at the moment we're founding a new department of our company in a different location that is 5 to 10 km away from the main location. We connected the new fc switches (Fabric OS v7.1.0c) with our old fabric (v6.4.3b) over DWDM. The new fc switches joined the common fabric and everything is working smoothly, except we are having a decreased performance issue, probably due to the latency. That's why I wanted to increase the buffers by setting the long distance parameter for the particular port.

 

On the new switch no alert is shown (DLS is activated). But on the old switches the software advices me to deactivate DLS. What is the reason for this? Should I activate the long distance parameter anyway, leaving DLS activated?

 

Thanks in advance for your help,

 

Michael

Frequent Contributor
Posts: 130
Registered: ‎02-05-2014

Re: Fabric OS v.6.4.3b: long distance: why should I turn off DLS?

You shouldn't turn it off. I assume you use Exchange based routing which in that can on FOS 7 you cannot turn off DLS. On FOS 6 you had the option but in effect you should leave this on.

 

I've written a piece on it here: http://erwinvanlonden.net/2014/01/dynamic-load-sharing-dls-and-in-order-delivery-iod/

 

Hope this helps.

 

Regards,

Erwin

Kind regards,
Erwin van Londen
Brocade Distinguished Architect
http://www.erwinvanlonden.net The Fibre Channel blog


Regular Contributor
Posts: 164
Registered: ‎05-11-2011

Re: Fabric OS v.6.4.3b: long distance: why should I turn off DLS?

Hi Michael,

 

please perform on both switches the command aptpolicy.

 

I think you have exchanged based routing active on the V7.1.0c switch and port based on the V6.4.3b switch.

When you have exchanged base routing you can not switch off DLS (both, V6 and V7), only when you have port based routing policy.

 

Best practise is to have exchanged base routing active on all switches.

 

 

Kind Regards
Ralf

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