DX NetOps

Hi

We have a item by name “Memory” in Component Details – Thresholds and Watches – Memory

Also we have one more item by name “Physical Memory” in Component Details – System Resources – File Systems - File Systems (RFC 2790)

Can someone please explain what are the difference in between these 2 items (Memory and Physical Memory ) and which one we need to monitor for RAM utilization.

Regards

“Physical Memory” in Component Details – System Resources – File Systems - File Systems (RFC 2790) should be good to monitor RAM utilization 

Roopesh,  Does Phani's reply answer your question?

Hi Rene,

thats fine but i wanted to know what are the difference in between these 2 items (Memory and Physical Memory ) 

Hi Roopesh,

“Memory” in Component Details – Thresholds and Watches – Memory

Is defined as a watch and can be found the watch report as:

Model typerfc2790App - 1watches

Name hrStorageUtilization
Developer ID 0xc40000
Author 
Last Modified Time: 
Model Type rfc2790App
Data Type Real
Expression ( ( REAL( hrStorageUsed.# ) / REAL( hrStorageSize.# ) ) * 100 )
Instance All
Active By Default Yes
Evaluate On Demand
Inheritable No
Threshold None

“Physical Memory” in Component Details – System Resources – File Systems - File Systems (RFC 2790)

Is defined as

Memory:  RFC-2790

 hrStorageType/0xc40783 - 1.3.6.1.2.1.25.2.3.1.2  hrStorageAllocationUnits/0xc4073b - 1.3.6.1.2.1.25.2.3.1.4  hrStorageSize/0xc4073c - 1.3.6.1.2.1.25.2.3.1.5  hrStorageUsed/0xc4073d - 1.3.6.1.2.1.25.2.3.1.6
  
                    Calculation:
 Mem Free: (hrStorageSize * hrStorageAllocationUnits) · (hrStorageUsed * hrStorageAllocatioUnits)
                    Mem Used: hrStorageUsed * hrStorageAllocatioUnits
                    Utilization: used / (free + used ) 
  
 **Note: hrStorageType is used to locate the specific entry which relates to physical RAM. hrStorage table also provide usitilzation information for virtual memory and file systems. We do not want these so we filter them out. If the value of hrStorageType is ·1.3.6.1.2.1.25.2.1.2· then we will use the same index across all attributes (ie if that value is found at position 2, then we will use the allocation units, size and used values at the same index).

The calculations are very similar if both are using the same source (RFC-2790), however there are other cases where different sources could be used such as UCDavisSNMPApp (NetSNMP) which is selected during discovery under “Memory” in Component Details – Thresholds and Watches – Memory but RFC-2790 will always use RFC-2790.

As to which is best to use to monitor is more of a personal preference.  Monitoring memory on Linux servers is extremely difficult due to the way the OS caches memory and as such would provide false memory usage allocations, therefore Spectrum gives the users this flexibility to decide which is best for them.

On top of that you can use Attribute Redirection to further customize on how you want to monitor by using different mib objects.

I hope this helps,

Glenn