Memory consumption by zabbix_agent(2.2.10) on RHEL7

[meetpradeepp]

Hello,

Am seeing zabbix_agent(2.2.10) on RHEL7 consuming somewhere in 450MB to 550MB on RHEL7 servers whereas for all other OS RHEL5 it takes around 50MB.

Are these values normal?

Thanks
Pradeep

[kloczek]

Probably you been looking on VSS column instead on RSS.
Agent consumes usually only few KB RSS.

[meetpradeepp]

Thank you for the reply.

I am using proc.mem to calculate the zabbix_agentd memory utilization as we had issue in past. The same monitor returns around 40MB on RHEL5 and 500+MB on RHEL7.

Am I missing something?

Thank you.

[kloczek]

https://www.zabbix.com/documentation/3.2/manual/config/items/itemtypes/zabbix_agent

proc.mem[<name>,<user>,<mode>,<cmdline>]
[..]
mode - possible values:
avg, max, min, sum (default)

In your case you are measuring sum of all VSSes of all zabbix_agentd processes.

$ /usr/sbin/zabbix_agentd -t "proc.mem[zabbix_agentd]"
proc.mem[zabbix_agentd]                       [u|464449536]
$ /usr/sbin/zabbix_agentd -t "proc.mem[zabbix_agentd,,,,vsize]"
proc.mem[zabbix_agentd,,,,vsize]              [u|464449536]
$ /usr/sbin/zabbix_agentd -t "proc.mem[zabbix_agentd,,max,,vsize]"
proc.mem[zabbix_agentd,,max,,vsize]           [u|94949376]
$ /usr/sbin/zabbix_agentd -t "proc.mem[zabbix_agentd,,max,,rss]"
proc.mem[zabbix_agentd,,max,,rss]             [u|4624384]
$ /usr/sbin/zabbix_agentd -t "proc.mem[zabbix_agentd,,max,,exe]"
proc.mem[zabbix_agentd,,max,,exe]             [u|389120]
$ /usr/sbin/zabbix_agentd -t "proc.mem[zabbix_agentd,,max,,lib]"
proc.mem[zabbix_agentd,,max,,lib]             [u|14872576]

As you see in all VSS space most of the space is used by shared libraries which code segments are shared not only amongst the zabbix_agentd processes.
Try to have look on /proc/<PID>/status where <PID> is PID of running zabbix_agentd process.

$ ps auxwf |  egrep "RSS|zabbix_agentd"
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
zabbix    2491  0.0  0.0  92492  2160 ?        S    Nov07   0:00 /usr/sbin/zabbix_agentd -c /etc/zabbix/zabbix_agentd.conf
zabbix    2492  0.0  0.0  92492  2500 ?        S    Nov07   0:35  \_ /usr/sbin/zabbix_agentd: collector [idle 1 sec]
zabbix    2493  0.3  0.0  92856  3100 ?        S    Nov07   4:37  \_ /usr/sbin/zabbix_agentd: active checks #1 [idle 1 sec]

Above RSS and VSZ columns are in KBs so it matches to what is possible to observe using zabbix_agend.

[meetpradeepp]

Thank you for detailed explanation. That clarifies a lot and also the number are nearly same to utilization our agent. Only last question remains on this topic is why same item on RHEL5 servers shows lesser utilization?

[kloczek]

Check ldd output on zabbix_agentd binary.
I'm betting that set of libraries is different and this is main factor that VSS size is different.

[meetpradeepp]

Darn thing. I need 3.0 on these machines to get specifics. Let me try to get these agent version and see the details. Am happy that you helped me in learning some more details.

Appreciate all your help.