Using RAID to improve availability is fine, but don’t forget to monitor it properly. Otherwise you will never know, that half of your mirror has already gone out of service for months.
Sometimes your favorite RAID controller will blink like the newest KIT gimmick inside your box, but only proper monitoring will really tell you about the problem.
For Nagios you will find appropriate checks at Monitoring Exchange.
I recommend check_raid by Steve Shipway for Linux software raid, but there is also a check_linux_raid contained in the Nagios plugins you most probably already installed on your system.
For 3ware controllers I have chosen the check provided at
You have to install the
tw_cli by 3ware to provide the information to this
script, but there are even Debian packages for
the necessary CLI tools.
Of course all these checks gather the information locally, but NRPE,
extend) or SSH will connect the local checks
to your Nagios.