eG Monitoring
 

Measures reported by VmgOSMemoryTest

The VmgOSMemoryTest reports the details about the physical memory of the VM/physical machine.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Total_phy_mem Indicates the total physical memory of the VM/physical machine. MB  
Used_phy_mem Indicates the used physical memory of the VM/physical machine. MB  
Free_phy_mem Indicates the free physical memory of the VM/physical machine. MB This measure typically indicates the amount of memory available for use by applications running on the target VM/physical machine.

On Unix operating systems (AIX and Linux), the operating system tends to use parts of the available memory for caching files, objects, etc. When applications require additional memory, this is released from the operating system cache. Hence, to understand the true free memory that is available to applications, the eG agent reports the sum of the free physical memory and the operating system cache memory size as the value of the Free physical memory measure while monitoring AIX and Linux guest operating systems.
Physical_mem_utilze Indicates the percent usage of physical memory. Percent Ideally, the value of this measure should be low. While sporadic spikes in memory usage could be caused by one/more rogue processes on the system, a consistent increase in this value could be a cause for some serious concern, as it indicates a gradual, but steady erosion of valuable memory resources. If this unhealthy trend is not repaired soon, it could severely hamper system performance, causing anything from a slowdown to a complete system meltdown.

You can use the detailed diagnosis of this measure to figure out which processes on the host are consuming memory excessively.
Available_phy_mem Indicates the amount of memory that is immediately available for use by processes, drivers, and the operating system. MB This measure is the sum of the zeroed memory (the memory that is filled with zeroes so that processes can be prevented from viewing it), Standby_mem and Free_phy_mem measures.

This measure is applicable only for Windows 2008 and above.
Modified_mem Indicates the the amount of physical memory that is assigned to the modified page list. MB The modified page list contains modifiable pages that have been faulted out of a working set. If the modified list has not been accessed for a long time, the memory manager will write the page to disk and then move it to the Standby list so that this memory can be made available for various other purposes such as allocation to a process, system use etc.

This measure is applicable only for Windows 2008 and above.
Standby_mem Indicates the physical memory that contains cached data and code that is not actively in use by processes, the system and the system cache. MB The standby memory is the memory that has been moved to page files but has not yet been written to the disk. If the system runs out of available free memory and zeroed memory, the memory on lower priority standby cache page lists will be repurposed before memory on higher priority standby cache page lists.

This measure is an aggregate of the following:

  • Standby Cache Core Bytes - The amount of physical memory that is assigned to the core standby cache page lists.
  • Standby Cache Normal Priority Bytes - The amount of physical memory that is assigned to the normal priority standby cache page lists.
  • Standby Cache Reserve Bytes - The amount of physical memory that is assigned to the reserve standby cache page lists.
This measure is applicable only for Windows 2008 and above.
Cached_mem Indicates the physical memory that contains cached data and code for rapid access by processes, drivers, and the operating system. MB This measure is the sum of the Standby_mem and Modified_mem measures.

This measure is applicable only for Windows 2008 and above.
Note:

While monitoring Linux/AIX operating systems, you may observe discrepancies between the value of the Physical memory utilized measure and the memory usage percentages reported per process by the detailed diagnosis of the same measure. This is because, while the Physical memory utilized measure takes into account the memory in the OS cache of the Linux/AIX VM/physical machine, the memory usage percent that the detailed diagnosis reports per process does not consider the OS cache memory.