The goal of this use case was to perform a second full backup of the same Oracle database to show the value of DD Boost host-based deduplication. Host-based deduplication means DD Boost software communicates with the Data Domain system to determine if a data block is unique. If the block is unique, it is sent to Data Domain system for protection. If the block is not unique, then it is not sent to Data Domain. The value of host-based deduplication is that it saves network utilization and space on the Data Domain appliance. DD Boost technology works transparently with RMAN, which means that RMAN sees a full database backup on the DD9300.
Before running second full backup, we modified the existing data by running a few transactions. To simulate real-world conditions, we used HammerDB and ran OLTP transactions for 10 minutes to create roughly five percent modified data. This modified data consisted of one percent inserts and four percent updates to ensure that the DD Boost software backed up new and modified data.
The following figure shows the use case 2 architecture.
Figure 20. Use case 2: Second full backup with 5% data modification
The following figure shows the local compression factor savings that are derived from the default algorithm (maximized throughput) on the Data Domain system for the second full backup. Tests show that only unique data was sent to Data Domain, and after local compression the final size was 109 GB. DD Boost host-based deduplication combined with local compression on Data Domain saves a significant amount of space. Performing daily full backups is easy because the space that is used on the Data Domain system is a small subset of the actual database size.
Figure 21. Second full backup compression ratio
Compression and deduplication save significant space on the DD9300. Dell EMC engineering test results show the compression factor was 16.7x: a 94 percent space savings for the second full backup.
The second full backup took significantly less time as compared to the first full backup. The second full backup of a 1.8 TB Oracle database took just 25 minutes—13 minutes less than the first full backup (38 minutes) and exhibited backup throughput of 1,191 MB/s. It is important that the time required for database backups remains predictable and minimized to reduce the impact to the business.