Computer Associates BABWBR1151S38 Implementation Guide - Page 38

Sample Calculations Next, calculate the amount of storage space you need for your online recovery data. You need to retain the last two backup sets in the library, so you need 9 tapes for the oldest set of recovery data and 9 tapes for the newest set. To store your recovery data you need 18 tapes. Therefore, your total storage requirement is as follows: 9 tapes for current backup + 18 tapes for recovery = 27 tapes Next, you calculate the capacity of the library by deducting cleaning slots: 20 slots/library - 1 cleaning slot = 19 available slots Therefore, you have a deficit of 27 - 19 = 8 slots and must do one of the following: ■ Add a library. ■ Compress the stored data. ■ Store only one set of recovery data online. 38 Implementation Guide