From a storage pool with a physical capacity of 100 TB, 30 volumes with a logical capacity of 5 TB each were created using thin provisioning. Currently, on average 40% of each volume's logical capacity has been written, and the data grows by a total of 2 TB each week. Ignoring data deletion and compression, when will the pool's utilization reach 80%?

Answer: A. In 10 weeks

The data currently written is 30 × 5 TB × 0.4 = 60 TB, which uses 60% of the 100 TB physical capacity. Only 80 − 60 = 20 TB can be added before reaching 80% (80 TB), so it takes 20 ÷ 2 = 10 weeks. Thin provisioning allocates physical capacity only for what is actually written, so here the total logical capacity of 150 TB exceeds the physical capacity. Writes become impossible once the physical capacity is used up, so monitoring utilization and adding capacity early is essential.

• A. Correct. (80 − 60) ÷ 2 = 10 weeks.
• B. This is the time until the pool is full (100%): (100 − 60) ÷ 2.
• C. This is based on 80% of the total logical capacity of 150 TB (120 TB). What is actually used is the physical capacity.