Host Status page shows higher than expected memory usage
Article ID: 152191
Updated On:
Products
Issue/Introduction
While monitoring the memory usage on a Symantec Messaging Gateway (SMG) system, the "Memory Usage" and "Memory Free" columns do not add up to the total memory available on the SMG appliance or virtual machine. SMG also appears to be using more memory than expected
Cause
This is expected behavior due to how current linux kernels manage memory.
The SMG Status > Host page only displays the "used" and "free" values for memory utilization but does not include the "shared", "buff/cache", or "available" values. This makes it appear as if memory utilization is much higher than expected even though the memory used for kernel buffers and cache is always available for user space processes should they need additional memory. In short, the operating system kernel makes use of free memory to optimize its performance but will release that memory for use when any other process needs it.
[support@smg ~]$ free
total used free shared buff/cache available
Mem: 3861616 2001780 554708 81352 1305128 1465916
Swap: 10534904 998400 9536504
Resolution
This is expected behavior and no remediation is required.
For more information on linux memory management, please see the following articles:
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