Overview

Just today (a specific time which I cannot tell) we had a time drif on the VM which most probably caused a FS to become a Read-Only. We don't know if the time drift caused the FS to become Read-Only, but we had to investigate anyway. There are couple command which you can use.

General

General trouble shooting isn't focused at specific component of the operation system, but it gives general idea of the system if there is performance issue, corruption and so on.

Logs

You can always check the logs. Very important log is:

/var/log/messages

That log records information about structural changes and other errors

Journals

You can also inspect the journals as follows:

Check journals since date

Commands

There are several commands, which can help you identify usage with the system:

top (topas in AIX) - Shows you overall usage of the system: CPU, memory, swap and processes.

lsof - Shows you a list of opened files.

netent - Shows you established connections, for example: netstat -na | grep 1521, will show you all connects for port: 1521 which have been established or a service is listening for.

e2fsck - BE CAREFUL with that command, usually it shouldn't be used very often as it can be dangerous if you don't know what you are doing. I general that command can check / fix corruption in a FS:

Check Corruption