A systems administrator has deployed a Dell Unity XT 380F system with 15x 1.92 TB SSD drives, in a RAID 5 dynamic pool. Shortly after deployment, the administrator wants to expand the capacity of the system and use larger drives to increase the density.
What will happen if the administrator adds 4x 3.84 TB SSD drives?
I'm going with B. Only half of the capacity of the new drives will be available. From Mixing Drive Sizes within Dell Unity XT Dynamic Pools in Dell training "When a new drive type is added, the pool must be expanded with a minimum number of drives. The number of drives must satisfy the RAID width plus the set hot spare capacity. If the number of larger capacity drives is not greater than the RAID width, the larger drive entire capacity is not reflected in the usable capacity.” To get the full capacity of the 3.84 TB SSD drives in a RAID 5 (4+1) dynamic pool, you need to add enough drives to meet the RAID width plus one requirement. In this case, the RAID width is 4, so you need at least 5 drives (4 data drives + 1 parity drive). Since we already have 4x 3.84 TB SSD drives, we would need to add at least 1 more 3.84 TB SSD drive to meet the requirement and make the full capacity of these drives available.