A thin clone is a writeable copy of a volume, which shares the same data blocks as the parent volume. This allows the administrator to provide a copy of the production database volume to the test environment without affecting the production data. It also allows to test the data without affecting the production data, and also it doesn't require additional storage space.

The Dell Unity XT 380F has a default spare space allocation of 4% of the total number of drives in a dynamic pool. So with 90x 1.92 TB SSDs, 4 drives will be allocated as spare space. These spare drives are used to automatically replace a failed drive, ensuring data availability and protection.

In Dell Unity XT storage systems, a dynamic pool is built using drive partnership groups. A drive partnership group is a group of drives that are combined to create a pool. A drive partnership group can be made up of SAS, NL-SAS, or Flash drives. In this case, the customer has a single pool built from 24x 800 GB SAS Rash 3 drives and 24x 1 6 TB SAS Rash 3 drives, and 14x 400 SAS Flash 2 drives. All drives are SAS type, and it's only one partnership group.

Choosing the highest capacity flash drives when designing a Dell Unity XT All-Flash system can provide several benefits, including lower physical space, power and cooling requirements.
Additionally, higher capacity drives can also improve system boot time, reduce maintenance and rebuild time, and decrease wear-leveling, performance, and redundancy requirements.