Cfs Merge Support - Cisco Nexus 5000 Series Configuration Manual

CFS Merge Support

• Physical topology level (physical scope)
• Between two selected switches
CFS Merge Support
CFS Merge is supported for CFS distribution over Fibre Channel.
An application keeps the configuration synchronized in a SAN fabric through CFS. Two such fabrics might
merge as a result of an ISL coming up between them. These two fabrics could have two different sets of
configuration information that need to be reconciled in the event of a merge. CFS provides notification each
time an application peer comes online. If a fabric with M application peers merges with another fabric with
N application peers, and if an application triggers a merge action on every notification, a link-up event results
in M×N merges in the fabric.
CFS supports a protocol that reduces the number of merges required to one by handling the complexity of the
merge at the CFS layer. This protocol runs per application per scope. The protocol involves selecting one
switch in a fabric as the merge manager for that fabric. The other switches do not have a role in the merge
process.
During a merge, the merge manager in the two fabrics exchange their configuration databases with each other.
The application on one of them merges the information, decides if the merge is successful, and informs all
switches in the combined fabric of the status of the merge.
In case of a successful merge, the merged database is distributed to all switches in the combined fabric and
the entire new fabric remains in a consistent state. You can recover from a merge failure by starting a distribution
from any of the switches in the new fabric. This distribution restores all peers in the fabric to the same
configuration database.
CFS Support for Applications
CFS Application Requirements
All switches in the network must be CFS capable. Switches that are not CFS capable do not receive distributions,
which results in part of the network not receiving the intended distribution. CFS has the following requirements:
• Implicit CFS usage—The first time that you issue a CFS task for a CFS-enabled application, the
• Pending database—The pending database is a temporary buffer to hold uncommitted information. The
Cisco Nexus 5000 Series NX-OS System Management Configuration Guide, Release 5.2(1)N1(1)
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Logical scope is not supported for FCS distribution over IP.
Note
Some applications (such as NTP) need to distribute the configuration to the entire physical topology.
Some applications operate only between selected switches in the network.
configuration modification process begins and the application locks the network.
uncommitted changes are not applied immediately to ensure that the database is synchronized with the
database in the other switches in the network. When you commit the changes, the pending database
overwrites the configuration database (also known as the active database or the effective database).
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