(Q) How do you defrag the AS/400's Hard Drives

(A) STRDSKRGZ

(Q) What are the differences between Mirroring (RAID1) and RAID5?

(A) Raid5 is faster reading, slower writing, and you have more usable disk space

    Raid1 needs 1b for each 1b you are protecting, whereas

    RAID5 needs 1b for each 8b you are protecting.

    RAID10 and RAID01 are faster than 1 or 5, requiring 1 drive 

    as the mirror for every drive you have..

    RAID1/10/01 is called mirroring.

    RAID5/6 is called striping.  6 adds a second stripe drive.

    RAID50/60 is a RAID 5/6 array with a RAID10 array around it.