[eddy]

Problem:

Cisco VSS 6500 switch with wrong memory utilization in monitor heatmap. heatmap showing the 6500 VSS switch with Mem 95%, but "show proc mem" with about 40% usage


Root Cause:

There are two types of VSS images, Modular IOS (denoted by the VZ in the image name) and Monolithic image (denoted by MZ). The currently used SNMP # $1.3.6.1.4.1.9.9.48.1.1.1.5.1*100.0/($1.3.6.1.4.1.9.9.48.1.1.1.6.1+$1.3.6.1.4.1.9.9.48 .1.1.1.5.1) only works on Monolithic image and it gets wrong MEM usage on Modular IOS (because this OID pulls the IOS base usage, not equal to kernel MEM usage in this case). The SNMP# ($1.3.6.1.4.1.9.9.109.1.1.1.1.12.1*100.0/($1.3.6.1.4.1.9.9.109.1.1.1.1.13.1+$1.3.6.1.4.1.9. 9.109.1.1.1.1.12.1) only works on Modular IOS, devices on MZ image return N/A for MEM usaged if they are applied this OID.

Solution:

Since these two types of images share the same System object ID. We can only differentiate them from device (image) level, if you find any VSS returns the false memory usage (95% or higher), which is not the case in your environment. Please Change the Retrieve MEM OID for these devices to:

$1.3.6.1.4.1.9.9.109.1.1.1.1.12.1*100.0/($1.3.6.1.4.1.9.9.109.1.1.1.1.13.1 + $1.3.6.1.4.1.9.9.109.1.1.1.1.12.1)

Right click VSS and select Shared Device Settings, click Advanced at the bottom left, in the pop-up window fill in the above formula in the Retrieve Memory field. Save the settings and monitor again to see whether NetBrain returns the correct value.