Implementing Arcserve Backup › Planning Storage Environments › Storage Capacity Requirements › Online Recovery Data Storage Requirements

Online Recovery Data Storage Requirements

You need to figure out how much recovery data you need to store online, in your robotic libraries. Data that is used primarily for archival purposes or for recovery after a catastrophe can be stored offline in a repository or vault. It is unlikely to be needed quickly. But recent backup data generally has to be available in a robotic library so that users can easily locate and swiftly recover the most recent, intact copies of the files they are most likely to lose.

To calculate the amount of recovery data you must store online

1. Estimate the size of an average, full backup.
2. Add the estimated size of an average incremental backup.
3. Multiply by the number of backup sets that your organization wants to have immediately available (“1” for the most recent, “2” for the two most recent, and so on). This is the amount of recovery data you need to keep online:

   recoverydata = (avgsizefull + avgsizeincrements) × numberbackupskept