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Occasional Contributor
Posts: 7
Registered: ‎04-24-2008

Buffer credit on 4900

Hi !

We have 2 4900 with 48 potrs on switch  ,   trunk on  2 ISL  between

How  I can find number of available buffer credit on switch ?

Occasional Contributor
Posts: 8
Registered: ‎04-08-2008

Re: Buffer credit on 4900

Hi,

use portbuffershow command, it will print the buffer allocations for the ports of a quad.

As the "help" page says:

portBufferShow - Displays the buffer usage information for a port group, or for all port groups in the switch.

Chris.

Occasional Contributor
Posts: 7
Registered: ‎04-24-2008

Re: Buffer credit on 4900

Hi Chris

Thank's  at answer , but  portbuffershow say me about 8 buffer at port

User     Port     Lx           Max/Resv    Buffer Needed          Link   Remaining
Port     Type    Mode          Buffers     Usage  Buffers     Distance  Buffers
----     ----    ----          -------     ------ -------     --------- ----------
   0        F      -               8          8       -             -
   1        F      -               8          8       -             -

skipped ...

15        E      -               8         26      26             2km      548

Value 8 a little for normal operation

At the same time not clearly how to use the remained 548   buffers   seems to me that

Occasional Contributor
Posts: 8
Registered: ‎04-08-2008

Re: Buffer credit on 4900

Hi Andrew,

To allocate more buffer you could play with portcfglongdistance and set longer distance

But i'm not sure you won't face trouble of sending too much frame on a short link

> portbuffershow
User     Port     Lx           Max/Resv    Buffer Needed          Link   Remaining
Port     Type    Mode          Buffers     Usage  Buffers     Distance  Buffers
----     ----    ----          -------     ------ -------     --------- ----------
  0       E     LS         46        46        46          20km
  1       E     LS         46        46        46          20km
  2       E     LS         46        46        46          20km
  3               -          8         0         -           -
   4       E     LS         46        46        46          20km
  5       E     LS         46        46        46          20km
  6       E     LS         46        46        46          20km
  7               -          8         0         -           -
   8       E       -          8        26        26           2km
  9       E       -          8        26        26           2km
10       E       -          8        26        26           2km
11       E       -          8        26        26           2km
12       E       -          8        26        26           2km
13       E       -          8        26        26           2km
14       E       -          8        26        26           2km
15       E       -          8        26        26           2km        212
----------------------------------------------------------------------------------

Occasional Contributor
Posts: 7
Registered: ‎04-24-2008

Re: Buffer credit on 4900

I believe that portlongdistance used only for ISL/trunk  on distant distance

And at me with buffer on local F  ports - they obviously do not suffice a problem

Are you  used portlongdistance for increase buffer on local port ?

Occasional Contributor
Posts: 7
Registered: ‎07-10-2012

Re: Buffer credit on 4900

Hi all

Portcfglongdistance is indeed only used for e-ports. Generally you should always have the same amount of buffers set on both sides of a link. If your device supports more than 8 buffers (as some storage arrays do), you could use the command portcfgfportbuffers to increase the buffers on a f-port.

Regards,

Rico

Frequent Contributor
Posts: 76
Registered: ‎04-17-2010

Re: Buffer credit on 4900

Many HBA's use fix amount of BB_Credits (many QLogic models use 3 afaik and that cannot always be changed, subject to platform / OS). I've never heard of the need of having the same amount of BB_Credits on the N_Port and F_Port. Brocade switches assign 8 credits by default, it's very rare that you need to change that setting. If you're running out of juice your issue is more likely to be in the area of fan-in/fan-out ratio and adapter queue depth, rather than BB_Credit count on node to fabric port connections ..

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