Fibre Channel (SAN)

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New Contributor
Posts: 4
Registered: ‎01-05-2017

The load is not evenly distributed over ISLs

[ Edited ]

Hello,

 

customer has 2 FC switches connected with 2 ISLs.

 

ISLs have the same speed, are not trunked, exchange-based routing policy used, DLS with lossless enabled,

FOS v7.3.1b, one fabric, HW model is SW7800.

 

portperfshow on ISL ports 0,4 shows that port 4 is 20x more utilized than 0.
0              4
=============================================
5.0m  101.5m

 

admin> dlsshow

DLS is set with Lossless enabled

E_Port Balance Priority is not set

 

islshow (hidden customer specific info)
1: 0-> 0 WWN 220 16-220 sp: 4.000G bw: 4.000G TRUNK CR_RECOV
2: 4-> 4 WWN 220 16-220 sp: 4.000G bw: 4.000G TRUNK CR_RECOV

 

admin> trunkshow (hidden customer specific info)
1: 0-> 0 WWN 220 deskew 15 MASTER

 

4: 4-> 4 WWN 220 deskew 15 MASTER

 

I found command dlsset --rebalance, but not tried, other possible step might be to offline/online one ISL a let rebalance it.

 

If you have similar experience, let me know, how to rebalance the load, ideally online.

 

Thanks!

Jan

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

Re: The load is not evenly distributed over ISLs

Hi Jan,

 

can look for the portperfshow for a longer time?

Do you have perhaps MAPS with FPI active?

 

 

Kind Regards
Ralf
New Contributor
Posts: 4
Registered: ‎01-05-2017

Re: The load is not evenly distributed over ISLs

[ Edited ]

Hello Ralf,

 

MAPS are enabled with legacy bottleneckmon, FPI will be enabled after update FOS to 7.4.1d.

 

Dashboard reports port 4 is more utilized than 0.

TX(%) 4(30.70) 4(31.00) 4(30.17) 4(27.93) 4(27.85) 4(27.07) 4(33.33)
      0(5.04)  0(3.69)  0(3.71)  0(2.63)  0(2.84)  0(2.72)  0(4.11)

 

Bottleneckmon reports port 4 congestion bottleneck at midnight due to backup activity.

(Congestion bottleneck on E-Port 4. 10.00 pct. of 30 secs. affected.)

 

linkcost

Port Cost
-------------------------
0 (E_PORT) 200 (STATIC)
4 (E_PORT) 200 (STATIC)

Regards,

Jan

New Contributor
Posts: 4
Registered: ‎01-05-2017

Re: The load is not evenly distributed over ISLs

Hello Ralf,

 

MAPS are enabled with legacy bottleneckmon, FPI will be enabled after update OFS to 7.4.1d.

 

Dashboard reports port 4 is more utilized than 0.

TX(%) 4(30.70) 4(31.00) 4(30.17) 4(27.93) 4(27.85) 4(27.07) 4(33.33)
      0(5.04)  0(3.69)  0(3.71)  0(2.63)  0(2.84)  0(2.72)  0(4.11)

 

Bottleneckmon reports port 4 congestion bottleneck at midnight due to backup activity.

Congestion bottleneck on E-Port 4. 10.00 pct. of 30 secs. affected.

 

linkcost

Port Cost
-------------------------
0 (E_PORT) 200 (STATIC)
4 (E_PORT) 200 (STATIC)

Regards,

Jan

Occasional Contributor
Posts: 11
Registered: ‎05-18-2015

Re: The load is not evenly distributed over ISLs

Brocade Moderator
Posts: 105
Registered: ‎04-27-2009

Re: The load is not evenly distributed over ISLs

Hi Jan,

 

is this imbalance seen all the time so also during the day or just during the backup job at night?

 

TL

If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution".

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers. All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider.
Brocade Moderator
Posts: 105
Registered: ‎04-27-2009

Re: The load is not evenly distributed over ISLs

If it's only reporting this imbalance during the backup activity it might be normal due to the Exchange Based Routing you are using. A backup exchange can be very large and would stay on one single path. Seen this several times.

If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution".

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers. All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider.

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