What data deduplication rates are expected?
First, redundancy will vary by application, frequency of version capture and retention policy. Significant variables include the rate of data change (few changes mean more data to deduplicate), the frequency of backups (more fulls makes compression effect higher), the retention period (longer retention means more data to compare against), and the size of the data set (more data, more to deduplicate). When comparing different approaches, be sure to compare with a common baseline. For example, some backup software can offer deduplication, but simultaneously these packages do incrementals-forever backup policies. For high-contrast comparison, they compare their dedupe effect against daily-full-backup policies with very long retention. (Data Domain tends to characterize dedupe behaviors in a daily-incremental, weekly-full backup policy with 1-4 months of retention.) The deduplication technology approach and granularity of the deduplication process will also affect compression rates. Data r
