Added hardware, disk, and raid failure checks.

The check executes in milliseconds with a dmesg containing 1039 lines. That's 0.06MB of data to load into memory from dmesg. That box has an uptime of 371 days.

What little resources the check uses, even if it multiplied by 100, is well worth the knowledge of knowing a disk is failing, before it becomes critical. Being able to preemptively replace a disk before we lose data or the server crashes, is worth the negligible resource usage.