Online Expert Day - HPE Data Storage - Live Now
April 24/25 - Online Expert Day - HPE Data Storage - Live Now
Read more
cancel
Showing results for 
Search instead for 
Did you mean: 

system performance tuning

maximodb
Occasional Contributor

system performance tuning

hi every body i want to check system performance i usually use glance,top,sar and swapinfo but i confused in something so i need explanation about memi every body i want to check system performance i usually use glance,top,sar and swapinfo but i confused in something so i need explanation about memory issue
ory issue

first i want check the memory usage i used glance i found this parameter so i need one shows me the differences between these parameters

Total VM : 810mb Sys Mem : 747mb User Mem: 533mb Phys Mem : 6.0gb
Active VM: 560mb Buf Cache: 275mb Free Mem: 4.5gb FileCache: na


actually the physical memory 6 giga and the free 4.5 i understand that but need to understand what is the "Active VM: 560mb" and "Total VM : 810mb"

and are these parameters belong to swap

i run swapinfo -mta
Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 12000 0 12000 0% 0 - 1 /dev/vg00/lvol2
reserve - 504 -504
memory 6132 839 5293 14%
total 18132 1343 16789 7% - 0 -

and with glance i found swap space and swap pesudo

Mb Mb Mb PCT START/ Mb
TYPE AVAIL USED FREE USED LIMIT RESERVE PRI NAME
dev 12000 0 12000 0% 0 - 1 /dev/vg00/lvol2
reserve - 504 -504
memory 6132 839 5293 14%Swap Device Type Avail Used Priority
--------------------------------------------------------------------------------
/dev/vg00/lvol2 device 11.7gb 0mb 1
pseudo-swap memory 6.0gb 839mb -1

total 18132 1343 16789 7%

also i need to understand the "pseudo-swap" i found this statement in book but don't understand "if we have 1 giga memory and 1 giga swap we can run 1.75 g processes " - 0 -

also i need to understand the "pseudo-swap" i found this statement in book but don't understand "if we have 1 giga memory and 1 giga swap we can run 1.75 g processes "

ok if we don't have the pseudo-swap how much processe in this situation 1 G ? i am asking


i hope any one help me to understand what is the prarmeters i must take care about .
many thanks .
2 REPLIES
maximodb
Occasional Contributor

Re: system performance tuning

i want to add issue i faced

the proplem i face i don't know the tool that tell me the accurate percentage of free memory

1- glance tell you when press "m"
Phys Mem : 6.0gb Free Mem: 4.5gb
2- glance tell you when press "w"
pseudo-swap memory 6.0gb 839mb
so from this statement we can say memory free is 6 - 839 say (1G) so the result is free memory 5 giga i don't know what is the true "4.5" or "5"
3- when use swapinfo -mat

dev 12000 0 12000 0% 0 - 1 /dev/vg00/lvol2
reserve - 503 -503
memory 6132 839 5293 14%
total 18132 1342 16790 7% - 0 -

so if we choose the memory + reserve we find the memory total 6 G and the user ( 503 + 839 ) = 1342 G and the free is ( 6 - 1342 ) so the result is 4802 G
so what is the true and acurate i am confused
Dennis Handly
Acclaimed Contributor

Re: system performance tuning

>I found this statement in book but don't understand "if we have 1 gig memory and 1 gig swap we can run 1.75 g processes"

This is saying roughly 75% of memory can be used for pseudo-swap. This may not be as simple for 11.31.

>if we don't have the pseudo-swap how much processes in this situation 1 G?

Yes but you don't want to do that. And on 11.31 you can't.

>so what is the true and accurate?

Memory is also used for the kernel and the various disk/file caches.