HP Cisco Nexus 5000 Cisco Nexus 5000 Series Switch CLI Software Configuration - Page 316

CFS Support for Applications Chapter 21 Using Cisco Fabric Services Send feedback to [email protected] 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 The following topics describe the CFS capabilities that support applications: • CFS Application Requirements, page 21-6 • Enabling CFS for an Application, page 21-7 • Locking the Network, page 21-8 • Committing Changes, page 21-8 • Discarding Changes, page 21-9 • Saving the Configuration, page 21-9 • Clearing a Locked Session, page 21-9 CFS Application Requirements All switches in the network must be CFS capable. Switches that are not CFS capable do not receive distributions and result in part of the network not receiving the intended distribution. CFS has the following requirements: • Implicit CFS usage-The first time you issue a CFS task for a CFS-enabled application, the configuration modification process begins and the application locks the network. • Pending database-The pending database is a temporary buffer to hold uncommitted information. The 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). 21-6 Cisco Nexus 5000 Series Switch CLI Software Configuration Guide OL-16597-01