Enterasys Networks X-PeditionTM manual Memory Management, Displaying System Status and Statistics

Memory Management

When the XSR boots up, the checksum of these files is calculated and stored in volatile memory. From then on any time the content of those files is changed the hash is recalculated and stored. You can access the hash value in the etsysConfigMgmtPersistentStorageChSum SNMP object and compare it with previous queries to detect configuration changes to the managed entity.

Displaying System Status and Statistics

The XSR’s numerous show commands, which are available in either privileged EXEC or Global configuration mode, display a broad array of system data such as:

•System name, port types and their status, CPU card revision, Flash memory and DRAM size, NIM cards and type, contact and system hardware data, image in Flash, and system location.

•XSR statistics: buffer counters, packets and NIM card status.

To display available show commands, issue the show ? command.

Some system data such as the product type and serial number, hardware revision number of the motherboard, and Ethernet port MAC addresses is stored in IDROM, a discrete area in Flash memory. You can view these parameters by issuing the show version command.

Refer to the XSR CLI Reference Guide for details about these commands.

Memory Management

The XSR provides memory management via its Resource Capacity feature. Resource Capacity marks an advance in flexibility over the hard-coded limits mechanism of earlier releases in that you can now choose which software modules to configure based on available memory per resource. Resource Capacity is designed to control resource creation so that the XSR does not run out of memory and operate improperly.

The XSR defines a resource as a software element which can be created or deleted in run time. When it is created it allocates memory by calling the memory management malloc function. When deleted, it returns the memory to common pools by calling free functions. Currently, approximately 45 resources including VPN tunnel, Access List entry, Route, and ARP request are tracked by a memory governor which can be accessed with the show resources command.

A resource can exist multiple times - for example, 5000 VPN tunnels - and each occurrence is considered an Instance by Resource Capacity. The maximum number of resource instances which can be created in a situation where practically no other resource is present constitutes that resource’s Extreme Limit although it is highly unlikely you will ever configure that many instances. Extreme limits are hard-coded, they can not be configured, and their size depends on the total amount of installed memory on the XSR.

Creating Resources

You can create a new instance of a given resource depending on the extreme limit for that resource and the current amount of available memory. Because you can keep creating resources until you run out of memory, you should find the right balance to satisfy your system operational needs - the XSR does not arbitrarily limit any particular resource.

For example, you may want to create a “VPN-heavy” configuration with many VPN tunnels, but only a few routes. In this case, the number of tunnels is not limited as it was in earlier releases. Alternatively, you can set up a “route-heavy” configuration with many routes but only a few tunnels. In either case, memory usage is balanced.

XSR User’s Guide 2-37