Data centers are complex beasts, and no amount of operator monitoring by itself can keep track of everything.  That’s why automated monitoring is so important.

So what should you monitor?  You can divide up your monitoring into a couple of strategic areas.  Just as with metrics collection, there is business & application level monitoring and then there is lower level system monitoring which is also important.

Business & Application Monitoring

• If a user is getting an error page or cannot connect
• If an e-commerce  transaction is failing
• General service outages
• If a business goal is met – or not
• Page timeouts or slowness

Systems Level Monitoring

• Backups completed and success
• Error logs from database, webserver & other major services like email
• Database replication is running
• Webserver timeouts
• Database timeouts
• Replication failures – via error logs & checksum checks
• Memory, CPU, Disk I/O, Server load average
• Network latency
• Network security

Tools that can perform this type of monitoring include Nagios,

Quora discussion – Web Operations Monitoring

Related posts:

1. Database Replication – What is it and why is it important?
2. Data Spot Checks – What are they and why are they important?
3. High Availability – What is it and why is it important?
4. Devops – What is it and why is it important?
5. What is disaster recovery and why is it important?