Here is the calculation for the Disk / Volume / RAM /below and example.
What object IDs (OIDs) does Orion NPM poll for volume information? What types of volume information does Orion NPM poll?
http://knowledgebase.solarwinds.com/kb/questions/1194/What+object+IDs+%28OIDs%29+does+Orion+NPM+poll+for+volume+information%3F+What+types+of+volume+information+does+Orion+NPM+poll%3F
Linux / Unix based Systems
You can run the MIB Walk for the Node in Question in order to find out what values been returned by the Node for required OID's as below.
Here is MIB walk tool details
Running SNMPWalk
******** MIb Walk Result from the Node **********
.1.3.6.1.2.1.25.2.3.1.3.1 = String: "Physical RAM"
.1.3.6.1.2.1.25.2.3.1.3.2 = String: "Virtual Memory"
.1.3.6.1.2.1.25.2.3.1.3.3 = String: "/"
.1.3.6.1.2.1.25.2.3.1.3.4 = String: "/proc"
.1.3.6.1.2.1.25.2.3.1.3.5 = String: "/dev/pts"
.1.3.6.1.2.1.25.2.3.1.3.6 = String: "/proc/bus/usb"
.1.3.6.1.2.1.25.2.3.1.3.7 = String: "/partB"
.1.3.6.1.2.1.25.2.3.1.3.8 = String: "/common"
.1.3.6.1.2.1.25.2.3.1.3.9 = String: "/grub"
.1.3.6.1.2.1.25.2.3.1.3.10 = String: "/dev/shm"
.1.3.6.1.2.1.25.2.3.1.3.11 = String: "/spare"
.1.3.6.1.2.1.25.2.3.1.3.12 = String: "/proc/sys/fs/binfmt_misc"
.1.3.6.1.2.1.25.2.3.1.4.1 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.2 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.3 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.4 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.5 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.6 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.7 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.8 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.9 = INTEGER: 1024
.1.3.6.1.2.1.25.2.3.1.4.10 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.11 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.4.12 = INTEGER: 4096
.1.3.6.1.2.1.25.2.3.1.5.1 = INTEGER: 1021591
.1.3.6.1.2.1.25.2.3.1.5.2 = INTEGER: 512034
.1.3.6.1.2.1.25.2.3.1.5.3 = INTEGER: 4232703
.1.3.6.1.2.1.25.2.3.1.5.4 = INTEGER: 0
.1.3.6.1.2.1.25.2.3.1.5.5 = INTEGER: 0
.1.3.6.1.2.1.25.2.3.1.5.6 = INTEGER: 0
.1.3.6.1.2.1.25.2.3.1.5.7 = INTEGER: 4232699
.1.3.6.1.2.1.25.2.3.1.5.8 = INTEGER: 17502476
.1.3.6.1.2.1.25.2.3.1.5.9 = INTEGER: 252879
.1.3.6.1.2.1.25.2.3.1.5.10 = INTEGER: 510795
.1.3.6.1.2.1.25.2.3.1.5.11 = INTEGER: 8468466
.1.3.6.1.2.1.25.2.3.1.5.12 = INTEGER: 0
.1.3.6.1.2.1.25.2.3.1.6.1 = INTEGER: 447260
.1.3.6.1.2.1.25.2.3.1.6.2 = INTEGER: 52
.1.3.6.1.2.1.25.2.3.1.6.3 = INTEGER: 2837178
.1.3.6.1.2.1.25.2.3.1.6.4 = INTEGER: 0
.1.3.6.1.2.1.25.2.3.1.6.5 = INTEGER: 0
.1.3.6.1.2.1.25.2.3.1.6.6 = INTEGER: 0
.1.3.6.1.2.1.25.2.3.1.6.7 = INTEGER: 2736606
.1.3.6.1.2.1.25.2.3.1.6.8 = INTEGER: 7646375
.1.3.6.1.2.1.25.2.3.1.6.9 = INTEGER: 4303
.1.3.6.1.2.1.25.2.3.1.6.10 = INTEGER: 5422
.1.3.6.1.2.1.25.2.3.1.6.11 = INTEGER: 8256
****************** Physical Disks ******************
hrStorageDescr = .1.3.6.1.2.1.25.2.3.1.3.3 = String: "/"
hrStorageAllocationUnits= .1.3.6.1.2.1.25.2.3.1.4.3 = INTEGER: 4096
hrStorageSize .1.3.6.1.2.1.25.2.3.1.5.3 = INTEGER: 4232703
hrStorageUsed = .1.3.6.1.2.1.25.2.3.1.6.3 = INTEGER: 2837178
Calculations :
Volume size 4232703 x 4096 17337151488 Bytes 16.146 GB
Volume used 2837178 x 4096 11621081088 Bytes 10.822 GB
space available 17337151488 - 11621081088 = 5716070400 5.323 GB .
Percentage 10.8/16.14 * 100 65%
****************************************************
hrStorageDescr = .1.3.6.1.2.1.25.2.3.1.3.1 = String: "Physical RAM"
hrStorageAllocationUnits= .1.3.6.1.2.1.25.2.3.1.4.1 = INTEGER: 4096
hrStorageSize .1.3.6.1.2.1.25.2.3.1.5.1 = INTEGER: 1021591
hrStorageUsed = .1.3.6.1.2.1.25.2.3.1.6.1 = INTEGER: 447260
Calculations : Physical RAM
Volume size 1021591 x 4096 4184436736 Bytes 3.897 GB
Volume used 447260 x 4096 1831976960 Bytes 1.706 GB
space available 1831976960 - 4184436736 = 2352459776 2.1 GB
Percentage 1.706/3.897 * 100 43%
*********************************************************
hrStorageDescr = .1.3.6.1.2.1.25.2.3.1.3.2 = String: "Virtual Memory"
hrStorageAllocationUnits= .1.3.6.1.2.1.25.2.3.1.4.2 = INTEGER: 4096
hrStorageSize .1.3.6.1.2.1.25.2.3.1.5.2 = INTEGER: 512034
hrStorageUsed = .1.3.6.1.2.1.25.2.3.1.6.2 = INTEGER: 52
Calculations : Virtual Memory
Volume size 512034 x 4096 2097291264 Bytes 1.953 GB
Volume used 52 x 4096 212992 Bytes 0.0001 GB
space available 212992 - 2097291264 = 2097078272 1.953 GB .
Percentage 0.0001/1.953 * 100 0.0%
///////////////////////////////////////////////////////////////
Adding Few more explanation here for Cisco Call Manager Showing 99% Memory Utilization in Orion .( just in case someone having this issue )
The reason you are seeing 99% is due to the Cisco MCS returning back those values.
Why its doing this, you have to Open Cisco TAC.
NPM is returning back the values its being supplied with, in this case showing 99%.
Poller type: Used .
- N.Memory.SNMP.CpqHostPhysicalMemory =
Memory poller for OpenVMS systems which support proprietary CPQ-Host MIB
Poller utilizes GetSubtree request with two OIDs to gather total and used memory:
cpqHoPhysicalMemorySize = 1.3.6.1.4.1.232.11.2.13.1.
cpqHoPhysicalMemoryFree = 1.3.6.1.4.1.232.11.2.13.2.
Total memory is computed using this formula:
memoryTotal = cpqHoPhysicalMemorySize * 1024
Used memory is computed using this formula:
memoryUsed = memoryTotal - (cpqHoPhysicalMemoryFree * 1024)
MIB Walk shows:
.1.3.6.1.4.1.232.11.2.13.1.0 = INTEGER: 3990 = cpqHoPhysicalMemorySize
.1.3.6.1.4.1.232.11.2.13.2.0 = INTEGER: 60 = cpqHoPhysicalMemoryFree
memoryTotal = 3990 * 1024 = 4085760
memoryUsed = 4085760 - (60 * 1024) = 4085760 – 61440 = 4024320
PercentUsed = 4024320/4085760 = 98.496% = 99%
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
For Linux Server for Poller assigned N.Memory.SNMP.NetSnmpReal
If poller assigned
N.Memory.SNMP.NetSnmpReal
/// memTotalReal = 1.3.6.1.4.1.2021.4.5.
/// memAvailReal = 1.3.6.1.4.1.2021.4.6.
/// memCached = 1.3.6.1.4.1.2021.4.15.
/// memBuffer = 1.3.6.1.4.1.2021.4.14.
/// UsedMemory = (totalMem - availMem - cachedMem - bufferMem) * 1024
.1.3.6.1.4.1.2021.4.5.0 = INTEGER: 2073620 (Total )
.1.3.6.1.4.1.2021.4.6.0 = INTEGER: 1869968 (Available )
.1.3.6.1.4.1.2021.4.15.0 = INTEGER: 88008 (cachedMemory )
.1.3.6.1.4.1.2021.4.14.0 = INTEGER: 51868 (BufferMemory )
( 2073620– 1869968– 88008– 51868 ) = 63776
63776 * 1024 = 65306624 bytes
--- Another Example ----
Yellow - Working SNMPWALK (supported net-snmp version)
Green - NON Working SNMPWALK (NON supported net-snmp version)
memTotalReal | .1.3.6.1.4.1.2021.4.5.0 | 1997828 | 4053 |
memAvailReal | .1.3.6.1.4.1.2021.4.6.0 | 19736 | 0 |
memCached | .1.3.6.1.4.1.2021.4.15.0 | 1216472 | 0 |
memBuffer | .1.3.6.1.4.1.2021.4.14.0 | 73948 | 0 |
Total Used | 687672 | 4053 |
Total Used x 1024 | 704176128 | 4150272 |
% used | - 34.42098119
| 100 |
ssCPUIdle | .1.3.6.1.4.1.2021.11.11.0 | 83 | 9 |
SSCPURAWIDLE | .1.3.6.1.4.1.2021.11.53.0 | 1253793743 | 1833365114 |
********************
Vmware ESX Memory Calculation
Supported Poller
The "Memory" Usage and the "Physical Memory" Utilization are calculated differently by Orion NPM.
Memory:
The Memory is the sum of the memory used by the processes listed in the HOST-RESOURCES-MIB:hrSWRunPerfTable (1.3.6.1.2.1.25.5.1).
The OID used is the hrSWRunPerfMem (1.3.6.1.2.1.25.5.1.1.2).
Physical Memory:
The Physical Memory is calculated based on the values populated in the HOST-RESOURCES-MIB:hrStorageTable (1.3.6.1.2.1.25.2.2.3).
The OIDs used are hrStorageSize (1.3.6.1.2.1.25.2.3.1.5), hrStorageUsed (1.3.6.1.2.1.25.2.3.1.6) and hrStorageAllocationUnits (1.3.6.1.2.1.25.2.3.1.4) .