Buffer of active checks results on agent side

[Shmuma]

Hello,

attached patch which implements buffer of active checks on agent in
case server is unreachable. There was small discussion about this idea
here: http://www.zabbix.com/forum/showthread.php?t=8361

The way it works:

1. There are two additonal unnecesary agentd's parameters:
ActiveChecksBufSize and ActiveChecksBufFile. First specify size of
buffer file in MB, second is the file path itself.

2. When agent trying to send result of active check to server and
fails by some reason (server is turned off, network is down, server's
database is down, etc) it stores result in this file.

3. Buffer file is divided by parts. Each part associated with active
check and has size protoportional active check refresh rate. So, we
have effective buffer usage for different active checks.

4. When connection betwen agent and server is restored (active check
sent sucessfully) and we have data in our buffer we send history data
to server. Data sent in one large XML block for each active check.

5. When there are no connection between agent and server, we can
restart agent freely: if it fails to obtain list of active checks from
server, it takes it from local buffer's list.

So, agent can work independently of server for some time. Of course
there will be no triggers/events, but we won't lose server's history
data. This can be very usefull for later analysis when something
really bad happen to our data center and zabbix server or network
connectivity is down.

This patch is against 1.4.4 release.

With best regards,
Max Lapan

[cpicton]

Thank you!!!!



This is the final piece of the implementaion issues which needed fixing for my Zabbix migration from nagios.

I will give feedback if i get eny errors

[bbrendon]

Does this work with 1.4.5 agents?
Anyone have a compiled windows agent with this?

[Shmuma]

No, with 90% probability this patch requires porting. I plan to do this in next few days.

Zabbix 1.5 beta contain similiar feaure, but store buffer in memory. I don't think this is a great idea: if machine with agent reboots, we lost historical data and have no way to get list of checks, so, if zabbix_server is not reachable, we won't get any infromation afer reboot. In situation when major failure occured (data center is overheated, network is broken or power supply failed), monitored servers can easily reboot in any time, and information about what happend with servers in such periods have great value. So we use our on-disk buffers and planning to do this later.

I have no windows version of agent with that patch, but it seems that I'll require one very soon. I'll post it here.

[stevenfoo]

1) Does this patch apply for Windows Zabbix agent?

2) I am new to Zabbix, how do I apply this patch? What are the steps involved?

Thanks
Steve

[Shmuma]

1. the patch is quite generic and doesn't use any unix-specific features. I didn't tested it on win32, but I'm sure that it should work.

2. on unix machine you should run 'patch -p1 < agent_buffer.patch' on top of zabbix 1.4.4 sources. I don't know much about windows version of zabbix, but I think that it also require modification of visual studio projects to build (there are two new files introduced by patch).