$12342.$ Tool for Reliability

Consider the following system with disks $1,2$ and $3.$

$--10$ Disk $1$s with $\backslash (1,000,000\backslash )-$hour MTTF

$--19$ Disk $\backslash (2$ s $\backslash )$ with $450,000-$hour MTTF

$--1$ Disk $3$s with $700,000-$hour MTTF

$--$ MTTR for single disk is $8000$ hours and $13,000$ hours for the system

$--$ p $($disk$)$ is $1$

$--$ G is $5$

$($a$)$ Find the MTTF of the system.

$($b$)$ Use the MTTF found above, to find the Reliability and MTTDL$.$ Which RAID level is best for each failure characteristic.

$($c$)$ Define the availability of a system based on its MTTF and MTTR$?$