Storage optimization
There are many different storage technologies: block storage, object storage, solid-state disks, memory, and so on. Each of these has a different set of characteristics that perform well in certain scenarios and poorly in others. For example, solid-state devices have high throughput and fast access but more expensive per-byte than spinning disks; if you are building a system that is designed for archiving large volumes of infrequently accessed data, using SSDs may not be cost-effective. Conversely, using a spinning disk for the random-access requests that a database is likely to make could lead to queries taking longer.
As with many parts of a system there are trade-offs to be made between cost-efficiency, storage reliability, and performance. By choosing the best-suited technology your system can be as efficient as possible with resources while remaining suitably reliable.