CHAPTER 1
ERX System Overview
SRP I/O module located in the rear of the chassis. If the primary SRP fails, the redundant SRP module assumes control without rebooting or initializing itself. (As a consequence, if you upgrade software, you must copy the software to the redundant SRP and reboot it.) For information about configuring and managing SRP module redundancy, see ERX System Basics Configuration Guide, Chapter 5, Managing Line Modules and SRP Modules.
After you install two SRP modules, the modules negotiate for the primary role. A number of factors determine which module becomes the primary; however, preference is given to the module in the
The SRP modules record their latest roles and retain them the next time you switch on the system. For information about installing SRP modules, see Chapter 3, Installing ERX Modules.
NVS Cards
If you have two SRP modules installed in a system, you can use NVS cards of different capacities on the SRP modules. The effective capacity of the
When you install new NVS cards or SRP modules, you must issue the synchronize command to match the file system of the NVS card on the redundant SRP module with the file system of the NVS card on the primary SRP module. (The NVS card on the redundant SRP module will hereafter be referred to as the redundant NVS card; the NVS card on the primary SRP module will hereafter be referred to as the primary NVS card.)
If the capacity of the primary NVS card is equal to or smaller than that of the redundant NVS card, the system copies all the files from the primary NVS card to the redundant NVS card. However, if the capacity of the primary NVS card exceeds that of the redundant NVS card, the system creates an invisible synchronization reserve file on the primary NVS card, provided that there is enough space for the file.
The purpose of the synchronization file is to prevent the creation of data that will not fit on the redundant NVS card. The file contains no useful data, and is not visible when you view the files in NVS. The size of the file is equal to the difference in capacities of the two NVS cards. For example, if the primary NVS card has a capacity of 224 MB, and the redundant NVS card has a capacity of 220 MB, the size of the synchronization file is 4 MB, and only 220 MB of space is available on the primary NVS card.
