How is Memory Utilization calculated for Linux server?

How is Memory Utilization calculated for Linux server?



Formula:
 (i) If Skip buffer and cache from monitoring (Applicable only for linux) option under Settings -> Performance Polling -> Servers Tab is not enabled. [By default, this option is not enabled]
Memory Utilization (%) = 100 -(((MemFree + Buffers + Cached)*100)/maxValue)
Memory Utilization (MB) = maxValue-(MemFree + Buffers + Cached)
(ii) If Skip buffer and cache from monitoring (Applicable only for linux) option under Settings -> Performance Polling -> Servers Tab is enabled.
Memory Utilization (%) = 100 - ((MemFree *100)/maxValue)
Memory Utilization (MB) = maxValue - MemFree

 In Telnet/SSH mode: 
testuser@testmachine:~$ free -b
              total                    used                 free                  shared            buff/cache      available
Mem:    12361719808  8122318848   274104320     370192384  3965296640  3541422080
Swap:   32212250624  4870012928   27342237696
MemFree corresponds to Mem:free 
Buffers + Cached corresponds to  Mem:buff/cache
maxValue corresponds to Mem:total
 (i) If Skip buffer and cache from monitoring (Applicable only for linux) option under Settings -> Performance Polling -> Servers Tab is not enabled.
Memory Utilization (%) = 100 -(((MemFree + Buffers + Cached)*100)/maxValue)
= 100 -(((274104320 + 3965296640)*100)/12361719808) 
= 65.705411336 = 65 %
Memory Utilization (MB) = maxValue-(MemFree + Buffers + Cached)
= 12361719808 - (274104320+3965296640) 
= 8122318848/(1024*1024) 
= 7746 MB
(ii) If Skip buffer and cache from monitoring (Applicable only for linux) option under Settings -> Performance Polling -> Servers Tab is enabled.
Memory Utilization (%) = 100 - ((MemFree *100)/maxValue)
          = 100 - ((274104320 *100)/12361719808)
          = 97.782636039 = 97%
Memory Utilization (MB) = maxValue - MemFree
= 12361719808 - 274104320
= 12087615488/(1024*1024) 
= 11527 MB

 In SNMP mode:
The UCD-SNMP-MIB file is used to get the memory usage for Linux servers. 
 Total Memory              .1.3.6.1.4.1.2021.4.5.0
 Free Memory          .1.3.6.1.4.1.2021.4.6.0
 Buffer Memory              .1.3.6.1.4.1.2021.4.14.0
 Cached Memory             .1.3.6.1.4.1.2021.4.15.0



                  New to ADManager Plus?

                    New to ADSelfService Plus?

                      • Related Articles

                      • Memory Usage Calculation (Linux- Telnet/SSH)

                        Total Memory Utilization Calculation: Linux Monitoring: Telnet/SSH For memory usage calculation using 'free -m'  command. Sample command output: root@root:~$  free -m                      total        used        free      shared  buff/cache   ...
                      • How is Memory Utilization calculated for FreeBSD server?

                        Memory Utilization is calculated using the below formula: Memory Utilization (%) =  (used / total) * 100 where, used - Used Memory total - Total Memory Telnet/SSH mode In Telnet/SSH mode, we use the following commands to obtain the memory usage ...
                      • How is CPU Utilization calculated for Linux server?

                        Telnet/SSH mode: We are using /usr/bin/vmstat 1 3 command to get the CPU Utilization for Linux servers.  Assume the output below:  ​ #/usr/bin/vmstat 1 3 ​ procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu----- r  b   swpd   ...
                      • How is Memory Utilization calculated in SUN Solaris server?

                        Memory Calculation We run the below command to check if the SUN server is a zone-supported server:  /usr/bin/prstat -n 1 -Z 1 1 2> /dev/null|grep -v "PID"|grep -v "Total:"  If the command gives the proper output then we conclude that the server is ...
                      • How is Memory Utilization calculated for AIX server?

                        Formula : Memory Utilization (%) = (Total Memory - Free Memory) / Total Memory where  Free Memory = Free + Buffers + Cached In Telnet/SSH mode:  We are using svmon -G command to get the memory usage value. For example consider the below output: ...