Cisco MDS 9000 Series Configuration Guide

Resolving Device Alias Merge Failures
The most common device-alias merge failure issues occur when merging databases. When a device-alias
merge fails, we recommend that you review the syslog messages on the switch in which the merge was initiated
in order to identify the issues. The application server in each fabric that is responsible for the merge is indicated
by the term Merge Master in the messages.
In this example, the syslog messages indicate that the merge failed as a result of a database mismatch:
2007 Apr 9 15:52:42 switch-1 %CFS-3-MERGE_FAILED: Merge failed for app device-alias, local
switch wwn 20:00:00:0d:ec:2f:c1:40,ip 172.20.150.38, remote switch wwn
20:00:00:0d:ec:04:99:40, ip 172.20.150.30
2007 Apr 9 15:52:42 switch-1 %DEVICE-ALIAS-3-MERGE_FAILED: Databases could not be merged
due to mismatch.
Use the device-alias distribute command to initiate a merge or remerge of device-alias databases. Use the
device-alias commit command to push a switch's device-alias database to all the other switches in a fabric.
If the switches whose device-alias databases are not merged (more than one merge master is shown in the
output of the show cfs merge status name device-alias command), then the device-alias commit command
causes the device-alias databases that are not merged to be overwritten.
Note
Device Alias Best Practices
This section lists the best practices that you should follow when creating and using device aliases:
• Device aliases should be used to simplify the management of world wide names (WWNs) whenever
possible. It is easier to identify devices with aliases rather than with WWNs. Hence, you should assign
aliases to WWNs to easily identify the WWNs.
• Device-alias names are case-sensitive.
• Operate device aliases in Enhanced mode whenever possible. In Enhanced mode, applications accept a
device-alias name in its native format, rather than expanding the alias to a port world wide name (pWWN).
Because applications such as zone server, Inter-VSAN Routing (IVR), Port Security Manager (PSM),
and Dynamic Port VSAN Membership automatically track and enforce device-alias membership changes,
you have a single point of change.
Interop mode VSANs do not accept Enhanced mode configurations.
Note
• Preplan device-alias configurations and implement a consistent naming convention.
• Keep documented backups of all device-alias configurations.
• Plan for what the final device-alias database should be after the merge, before attempting to resolve
merge failures. This can prevent traffic disruptions caused by accidentally overwriting device-alias entries.
Cisco MDS 9000 Series Fabric Configuration Guide, Release 8.x
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Distributing Device Alias Services
Resolving Device Alias Merge Failures

Cisco MDS 9000 Series Specifications

General

Category	Switch
Operating System	Cisco NX-OS
Ports	Varies by model
Protocols	Fibre Channel (FC), Fibre Channel over IP (FCIP), iSCSI
Redundancy	Redundant supervisors, power supplies, and fans
Management	Cisco Data Center Network Manager (DCNM), CLI, SNMP
Virtualization Support	VSANs (Virtual SANs)
Security Features	Fibre Channel Security Protocol (FC-SP)
Hot Swappable Components	power supplies, fans
Power Supply Options	AC and DC options available