difference between active and non avtice

[Colttt]

Hello,

can somebody tell me the difference between zabbix agent and zabbix agent(active)?!

thnaks

[Rob]

The 'Zabbix agent' checks are performed from the zabbix server. It connect to the agent via the IP or DNS name set for that host.

An active check works the other way round. Every few minutes, the agent connects to the server and asks for a list of active checks. If you have say, an active check for CPU load set for every 60 seconds, the agent will then send this value in every 60 seconds.

Active checks are great for hosts behind firewalls as they only require outbound access to the Zabbix server. We use them a lot. They also cut the load on the Zabbix server. The only negative is that it's harder to tell that a host is down if you don't have any non-active checks. You have to set a trigger up to alert you if no data has been received for say, 5 minutes for an item such as the hostname or something else simple.

You can mix and match active and passive checks on the same host if you want. I've seen recommendations in the past, to have just one passive check to allow you to be alerted if the host can't be contacted, and the rest as active checks to reduce load on your server.

[Alexei]

Another advantage of active checks is ability to buffer data on agent side in case if Zabbix Server or Proxy is not available. No data loss!

The buffer is controlled by two configuration parameters from zabbix_agentd.conf:

BufferSend
BufferSize

See http://www.zabbix.com/documentation/.../zabbix_agentd for more details.

[pfouquet]

The buffer is controlled by two configuration parameters from zabbix_agentd.conf:

BufferSend
BufferSize

We are testing BufferSend and BufferSize.
It seems that the data are send to the server or proxy only when time or size is reached.

So it looks impossible to have a max data preservation in case of server failure and a respectable time and tcp communication to the server in normal case.

Is it possible to have this kind of configuration:

BufferSend=5 # Send every 5 sec in normal mode
BufferSize=100 # Send every 100 items in normal mode
BufferMaxSend=3600 # Buffering 3600 sec in case of server failure
BufferMaxSize=65535 # Buffering 65535 items in case of server failure

Thanks for your help

[Alexei]

Is it possible to have this kind of configuration:

BufferSend=5 # Send every 5 sec in normal mode
BufferSize=100 # Send every 100 items in normal mode
BufferMaxSend=3600 # Buffering 3600 sec in case of server failure
BufferMaxSize=65535 # Buffering 65535 items in case of server failure

It is not possible currently. Please consider registering a feature request at https://support.zabbix.com/browse/ZBXNEXT

[wizard-ict]

We are testing BufferSend and BufferSize.
It seems that the data are send to the server or proxy only when time or size is reached.

So it looks impossible to have a max data preservation in case of server failure and a respectable time and tcp communication to the server in normal case.

Is it possible to have this kind of configuration:

BufferSend=5 # Send every 5 sec in normal mode
BufferSize=100 # Send every 100 items in normal mode
BufferMaxSend=3600 # Buffering 3600 sec in case of server failure
BufferMaxSize=65535 # Buffering 65535 items in case of server failure

Thanks for your help

I would have actually expected that to be the default action for this parameter. I can't see a lot of point buffering all the data when the server is online, it has to be sent eventually so you aren't saving anything, but buffering in case the server is unreachable makes complete sense.

Please do log this as a feature request, it would be useful for me also.

[richlv]

We are testing BufferSend and BufferSize.
It seems that the data are send to the server or proxy only when time or size is reached.

So it looks impossible to have a max data preservation in case of server failure and a respectable time and tcp communication to the server in normal case.

Is it possible to have this kind of configuration:

BufferSend=5 # Send every 5 sec in normal mode
BufferSize=100 # Send every 100 items in normal mode
BufferMaxSend=3600 # Buffering 3600 sec in case of server failure
BufferMaxSize=65535 # Buffering 65535 items in case of server failure

Thanks for your help

please note that, if i understand this correctly, size does not impact when data is sent, but when data is discarded. similarly, time does not impact what is buffered, only when it is sent.

as such, i don't think suggested BufferMaxSize would accomplish anything - you can just set the current buffersize higher.

again, if i understood this correctly, BufferMaxSend would just make agent back off in case server is unreachable - is that really the desired outcome ?

[pfouquet]

again, if i understood this correctly, BufferMaxSend would just make agent back off in case server is unreachable - is that really the desired outcome ?

Yes, we need parameters for keeping in the agent buffer (postpone data), a certain time or size of data in case of server or proxy unreacheable.

Older data than the BufferMaxSend or BufferMaxSize can be discarded if server is always unreacheable.

[richlv]

but why not just increase buffersize ?

[pfouquet]

but why not just increase buffersize ?

During our tests, if we use :
BufferSend=3600
BufferSize=65535

Agent send data to the server only every one hour or after 65535 collected metrics.
Not really usefull for proactive supervision

[richlv]

right. but if you don't touch BufferSend ?

[pfouquet]

I'v try this configuration:
BufferSend=30
BufferSize=65535

and disable zabbix server during 09 minutes (between 09:06 and 09:15).

After restarting it, we have lost many many data:
2012.Fév.22 09:15:30 0.3167
2012.Fév.22 09:15:25 0.35
2012.Fév.22 09:15:20 0.3333
2012.Fév.22 09:15:15 0.3
2012.Fév.22 09:15:10 0.3167
2012.Fév.22 09:15:05 0.2667
2012.Fév.22 09:11:29 0.3667 <---- just one data for the 9 minutes of failure
2012.Fév.22 09:06:47 0.8519
2012.Fév.22 09:06:42 0.9091
2012.Fév.22 09:06:37 0.7647
2012.Fév.22 09:06:32 0.75
2012.Fév.22 09:06:27 0.8571
2012.Fév.22 09:06:06 1.7167
2012.Fév.22 09:06:00 1.85
2012.Fév.22 09:05:55 1.85
2012.Fév.22 09:05:50 1.75

[richlv]

hmm, this doesn't seem to match my expectations. apparently there's either a problem, or proper documentation is needed for this - could you please file a new zbx report on the issue tracker ?

thanks

[pc99096]

ok so how is it working?

what if i set let's say
BufferSend=5
BufferSize=65535

and zabbix server will be unavailable for 10 minutes?
will be all values dropped after 5 seconds even when buffer not full?

[richlv]

no, it will try to keep up to 65k values. in memory