The planning team analyzed data usage patterns to establish performance objectives and availability requirements for their two object types. Summary objects are used for 30 calendar days, and response time must be fast during that period; however, at the end of 30 calendar days, the objects are no longer used and might be deleted. Detail objects have a more complex life cycle. During the first seven calendar days after creation, detail objects are accessed frequently, and fast response is needed. After that time, retrieval frequency drops, as does the response-time requirement. Detail objects are rarely used after 180 calendar days, but the company is required by law to keep them on file for five years (1 825 calendar days).
Table 1 summarizes the characteristics of the company’s objects.
| Characteristics | Detail objects | Summary objects |
|---|---|---|
| Object size in bytes | 64 000 | 3 000 |
| Number created per workday | 10 000 | 10 000 |
| Number of workdays that fast retrieval is required (less than 1-second response time) | 7 | 30 |
| Number of calendar days that medium retrieval is required (less than 20-second response time) | 180 | — |
| Number of calendar days from creation after which the object is rarely accessed | 180 | — |
| Number of calendar days from creation after which the object can be deleted (5 years) | 1 825 | 30 |
| Maximum retrieval rate required (objects per hour) for fast retrieval | 1 000 | 2 000 |
| Maximum retrieval rate required (objects per hour) for medium retrieval | 100 | — |
| Maximum retrieval rate required (objects per hour) for slow retrieval | 10 | — |
| Number of backup copies required | 1 | 0 |