DRBD monitoring under Cricket

1.1. What is DRBD?

DRBD is a free software which allows replication of filesystems thru a TCP/IP network. The main part is a kernel module. Associated tools and scripts allow the definition and maintenance of the mirrored filesystems. DRBD can be used to build high-availability servers.
More details can be found on http://www.drbd.org/.

1.2. What is Cricket?

Cricket is a free system for monitoring almost all what can be monitored ;-). Mainly used by system/network administrators, it can gather and graph all kind of data and/or devices: routers, servers, swithes, applications, temperature, cpu load, bandwidth and more. Cricket configuration is completely open and can be tuned to integrate lot of extra data.
More details can be found on http://cricket.sourceforge.net/.

1.3. Why collect statistics?

A system/network administrator _must_ collect statistics. Once an application or a device installed, statistics can give us lot of useful information:

Does the device run fine? (Status)
Do we need to perform some fine-tuning? (Performance)
Do we need to upgrade it or replace it? (Provisioning)
Do we need to be notified in case of specific event (Alarm)
...

1.4. Existing DRBD monitoring?

Once I installed my first DRBD replica between two Linux boxes, I started to search for some monitoring features or extra-tools. Standard monitoring is done via the /proc filesystem:

     [root@ftp1 root]# cat /proc/drbd
     version: 0.6.12 (api:64/proto:62)
 
     0: cs:Connected st:Primary/Secondary ns:11632424 nr:0 dw:1030048 dr:10635537 pe:0 ua:0
     [root@ftp1 root]#

Very simple, clear for the system administrator but what about history? readable format for the managment? Even Google results were negative so, I wrote my own scripts.

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Installation

DRBD monitoring under Cricket

1. Introduction

1.1. What is DRBD?

1.2. What is Cricket?

1.3. Why collect statistics?

1.4. Existing DRBD monitoring?