What Factors Affect the DRS Task Speed and How Do I Estimate the Time Required?

Factors

• Read throughput of the source database

  The higher the read throughput is, the faster the migration speed can be, and the less the time required can be. Factors that affect the throughput include but are not limited to server specifications, load, disk I/O performance, and database traffic limiting.

• Write throughput of the destination database

  The higher the write throughput is, the faster the migration speed can be, and the less the time required can be. Factors that affect the throughput include but are not limited to server specifications, load, disk I/O performance, and database traffic limiting.

• Available network throughput

  The higher the available network throughput is, the faster the migration speed can be, and the less the time required can be. Factors that affect network throughput include but are not limited to available bandwidth, firewalls, and network device traffic limiting.

• Network quality and delay

  The shorter the network latency is, the faster the migration speed can be, and the less the time required can be. The factors include but are not limited to the distance between the source or destination database and the DRS instance. Poor network quality (for example, high packet loss rate) reduces the migration speed.

• DRS instance specifications

  The larger the DRS instance specifications are, the faster the migration speed can be, and the less the time required can be.

• Model and distribution of source data

  Such factors include whether there is a primary key, whether there is a partition table, whether there is a heap table, average data volume in a single row, number of tables, and number of indexes.

• Whether there is data in the destination database

  Existing data in the destination database may cause data conflicts during migration, resulting in performance deterioration.

• Whether the destination database has a trigger

  If the destination database has a trigger, the write performance may deteriorate during migration.

• Destination database backup and log settings

  If not necessary, disable destination database backup and transaction logs during the migration to improve migration performance.

• Incremental data generation speed of the source database

  The faster the incremental data is generated in the source database, the longer it takes to balance the incremental data.

• Number of DRS tasks

  If performance bottlenecks caused by other factors are not considered, you can split DRS tasks by table to improve the overall migration performance.

Estimated Migration Duration

There are many factors that affect the migration duration. No common method can be used to calculate the migration duration. You can evaluate the migration duration by referring to Real-Time Synchronization Specification Description. You are advised to create a test task in an environment with the same specifications, load, network configuration, and data model as the instance to be migrated to evaluate the migration duration.

Migration Speed Improvement

Full

• If the network bandwidth of the source or destination database is limited, increase the bandwidth.
• If the load on the source database is not heavy, increase the number of concurrent read and write operations.
• Expand the DRS task specifications.

Incremental

• If the network bandwidth of the source or destination database is limited, increase the bandwidth.
• If the performance is limited by the DRS specifications, use a DRS task with higher specifications.
• If the replay is slow, increase the number of concurrent replay requests.