Answer:
According to the requirements of users of the system, RAID 10 is more suitable option.
Explanation:
As mentioned previous server is running RAID 5, Which takes a lot of time to manage parity while reading or writing data.
On the other end RAID 10 is the combination of RAID 1 and RAID 0, It has the the features of both system.
According to the users requirement, unscheduled downtime or data loss can cannot be tolerated. So RAID 10 has the ability to access the data from multiple disks. If one disk i down, required data can be gathered from other disks.
It creates multiple duplicates of data, so risk to lose data has also been reduced.
In both aspects, RAID 10 is better than RAID 5, so he choose RAID 10 for up gradation.