Is my network healthy? Important CLI info – (memory issues)

What else is important when you are logged in to the router/switch? We talked about the ‘show version’ command, there are more important things to check. Memory for example. Memory utilization is monitored by right clicking on the task bar and selecting task manager. Just kidding, you get to see the memory info by running the ‘show memory’ command. This will generate a list of all the memory address space and what is allocated to what. Not the friendliest command, but we are mainly interested in the first few lines that it generates. The output is divided into processor and IO and we want both of them to not be over utilized. How do you know if you are over utilized? The device will show one of the following symptoms: * The console or log message: “%SYS-2-MALLOCFAIL: …” * The show processor memory command is displayed no matter what command you type on a console. * No output from some show commands. * “Low on memory” messages. * The console message “Unable to create EXEC – no memory or too many processes”. * Refused Telnet sessions. * Router hanging or no console response. Also the command ‘show memory failures alloc’ has some lines following it. There are things to do with memory issues, adding memory of course, but also try to put the latest recommended ios version to avoid memory leaks. If you want to see what process takes all the memory, execute the ‘show process memory sorted’ command. Normally on routers the number one consumer is the ip routing protocol (eigrp/bgp/ospf), if you see ARP or SNMP or other things that should not be using a lot of memory that might explain the problem. Here is a sample of it: This image was lost when Geocities went down, comment if you need it and I’ll try to reproduce More info can be found at: http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a00800a6f3a.shtml There are a few other things to look at, but that will be next time …