How to partition internal Flash memory on Cisco routers
Enabling one router to maintain two or more software images.
By Brad Reese, Network World | Network World US | Published: 00:00, 05 May 2008
On most class B Flash file systems, you can partition banks of Flash memory into separate, logical devices so that the router can hold and maintain two or more different software images.
This partitioning allows you to write software into Flash memory while running software in another bank of Flash memory. To partition Flash memory, you must have at least two banks of Flash memory. A bank is a set of four chips.
This requirement includes systems that support a single SIMM that has two banks of Flash memory. The minimum partition size is the size of a bank.
This command is an example of how to partition Flash memory:
Router(config)#partition flash partitions [size1 size2]
This following command is for Cisco 1600 and 3600 series routers:
Router(config)#partition flash-filesystem: [number-of-partitions][partition-size]
This task succeeds only if the system has at least two banks of Flash, and the partitioning does not cause an existing file in Flash memory to be split across the partitions.
For all platforms except the Cisco 1600 series and 3600 series routers, Flash memory can only be partitioned into two partitions.
For the Cisco 1600 and 3600 series routers, the number of partitions that you can create in a Flash memory device equals the number of banks in the device.
Issue the show flash-filesystem: all command to view the number of banks on the Flash memory device. The number of partition size entries you set must be equal to the number of specified partitions.
For example, the partition slot0: 2 8 8 command configures two partitions to be 8 MB in size each.
The first 8 corresponds to the first partition; the second 8 corresponds to the second partition.
For more information on how to partition Flash, refer to Cisco Router Memory Commands.