Manually Inserting Entries Into Alpa Cache; Displaying The Alpa Cache Contents; Clearing The Alpa Cache; Configuring Port Guard - Cisco MDS 9000 Series Configuration Manual

Configuring Port Guard

S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m

Manually Inserting Entries into ALPA Cache

To manually insert entries into the ALPA cache, follow these steps:
Command
Step 1
switch# config t
Step 2
switch(config)# tlport alpa-cache interface
fc1/2 pwwn 22:00:00:20:37:46:09:bd alpa 0x02
Step 3
switch(config)# tlport alpa-cache interface
fc1/3 pwwn 22:00:00:20:37:46:09:bd

Displaying the ALPA Cache Contents

The show tlport alpa-cache command displays the contents of the ALPA cache.
switch# show tlport alpa-cache
---------------------------------------------------------
alpa
---------------------------------------------------------
0x02
0x04
The first entry indicates that if a device with a pWWN of 22:00:00:20:37:46:09:bd is exported on TL
port fc1/2, then the pWWN is allocated an alpa 0x02 (if available).

Clearing the ALPA Cache

The clear tlport alpa-cache command clears the entire content of the ALPA cache.
Configuring Port Guard
The port guard feature is intended for use in environments where the system and application environment
does not adapt quickly and efficiently to a port going down and back up, or to a port rapidly cycling up
and down, which can happen in some failure modes. For example, if a system takes five seconds to
stabilize after a port goes down, but the port is going up and down once a second, this might ultimately
cause a more severe failure in the fabric.
The port guard feature gives the SAN administrator the ability to prevent this issue from occurring in
environments that are vulnerable to these problems. The port can be configured to stay down after the
first failure, or after specified number of failures in a specified time period. This allows the SAN
administrator to intervene and control the recovery, avoiding any problems caused by the cycling.
Using the port guard feature, you can restrict the number of error reports and bring a malfunctioning port
to down state dynamically. A port can be cofigured to go into error-disabled state for specific types of
failures.
A general link failure caused by link-down is the superset of all other causes. The sum of the number of
all other causes equals to the number of link-down link failures. This means a port is brought to down
state when it reaches the maximum number of allowed link failures or the number of specific causes.
The causes of link failure can be any of the following:
•
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
2-32
pWWN
22:00:00:20:37:46:09:bd
23:00:00:20:37:46:09:bd
ESP trustsec-violation
Purpose
Enters configuration mode.
Configures manual entries into the ALPA cache.
Removes this entry from the ALPA cache.
Interface
fc1/2
fc1/2
Chapter 2 Configuring Interfaces
OL-19445-02, Cisco MDS NX-OS Release 4.2(x)