Distributed poller not improving the polling performance

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Hello,
I was trying improve my librenms performance for last couple months and I feel strange when I setup distributed pollers by following the Librenms Docs. would be appreciated if you could point me the right way.

currently there are about 400 devices and 7000 ports. we have 1 main server and 2 poller servers for dedicated sites.
we have installed rrdcached and memcached as recommended in Librenms Performance Docs. however, it is noticed that the dedicated poller even slower due to the long distance.

when I poll the device from the poller, the result is:

./poller.php 176 2018-06-23 09:03:24 - 1 devices polled in 156.0 secs
SNMP [62/5.84s]: Get[23/0.95s] Getnext[0/0.00s] Walk[39/4.88s]
MySQL [364/98.79s]: Cell[21/5.26s] Row[23/5.82s] Rows[51/16.64s] Column[2/0
RRD [366/49.30s]: Update[183/0.05s] Create [0/0.00s] Other[183/49.25s]

when I poll from the main server, the result is:

./poller.php 176 2018-06-24 07:44:05 - 1 devices polled in 74.91 secs
SNMP [61/64.94s]: Get[22/5.90s] Getnext[0/0.00s] Walk[39/59.04s]
MySQL [364/0.16s]: Cell[21/0.01s] Row[23/0.00s] Rows[51/0.03s] Column[2/0.00s] Update[265/0.12s] Insert[2/0.00s] Delete[0/0.00s]
RRD [366/0.27s]: Update[183/0.02s] Create [0/0.00s] Other[183/0.26s]

the snmp query from poller is quicker but MySQL and RRD is much slower , that cause the whole poller process is much slower on poller ( 156s vs 74s). Is this normal?

I have installed memcached and rrdcached and they both seems receiving and responding correctly. did I miss anything or somewhere I misunderstood?

Here is the output of validate.php:

-bash-4.2$ ./validate.php
====================================
Component | Version
--------- | -------
LibreNMS  | 1.40
DB Schema | 251
PHP       | 7.0.30
MySQL     | 5.5.56-MariaDB
RRDTool   | 1.6.0
SNMP      | NET-SNMP 5.7.2
====================================

[OK]    Composer Version: 1.6.5
[OK]    Dependencies up-to-date.
[OK]    Database connection successful
[OK]    Database schema correct

Thanks and regards,
Roger

Hello,
Could anyone help me with the distributed poller? As I mentioned in the description, the distributed poller actually taking longer time than the main server. I’m wondering if there are any misconfiguration in my system?
Could anyone using distributed poller show me the result when polling from the distributed poller?
Thanks in advance.
Cheers,
Roger

Hi,

show config.php from main serwer and pollers.

Distributed polling doesn’t help in high latency situations. You’re going from having high latency in snmp from the main poller to your remote device to having high latency for rrd updates and mysql from the remote poller to your central install.

You’re only option is to poll remotely and try and tune snmp to deal with that.

Hi, I run into the same issue. I guess the documentation is misleading here:

https://docs.librenms.org/Extensions/Distributed-Poller/

“LibreNMS has the ability to distribute polling of devices to other machines.
These machines can be in a different physical location and therefore minimize network latency for devices that are a considerable distance away or are behind NAT firewalls.”

Regards, MatK