Why Does the Progress Bar of a Full Data Migration/Synchronization Task Not Move for a Long Time?
The following reasons may cause the progress bar of a full data migration/synchronization task not move for a long time:
Large data size in a single table. Progress calculation of a full data migration/synchronization task is affected by the number of source tables. If a source table contains a large volume of data, DTS requires a long period of time to migrate the data. This may cause the progress bar not move for a long period of time.
Network issue: If the network bandwidth is insufficient or network interruptions occur during full data migration/synchronization, the progress bar may not move for a long period of time. Check the network bandwidth and network condition to determine whether the progress bar stuck is caused by a network issue.
High database workload: If the source or destination database carries a high workload during full data migration/synchronization, the task progress will be affected. Disks for databases have read and write upper limits. When some other tasks occupy much read/write bandwidth in a certain period of time, the progress of the DTS task is affected.
Why Is the Latency of Incremental Data Migration/Synchronization High?
The following reasons may cause high latency in incremental data migration/synchronization:
Network issue: If the network bandwidth is insufficient or network interruptions occur during incremental data migration/synchronization, the data migration/synchronization latency increases.
Frequent data updates: If the data in the source database is frequently updated during incremental data migration/synchronization, the latency increases. DTS needs to synchronize each data update to the destination database. If frequent data updates are performed, the data migration/synchronization jobs stimulate, and the data migration/synchronization latency increases.
Low disk read and write speeds: If the read and write speeds of the disk for the destination database are slow, the data migration/synchronization speed is slow, and the data migration/synchronization latency increases.
Low DTS instance specification: If a large volume of data needs to be migrated/synchronized but the specification of the DTS instance that is used for the migration/synchronization task does not meet the requirements, the data migration/synchronization latency increases.
According to the reason for the high latency, you can take one of the following measures to reduce data migration/synchronization latency:
Increase the network bandwidth or optimize the network connectivity to speed up data transmission and improve the data transmission stability.
After the data migration/synchronization task is complete, optimize the business logic to reduce write swarms and large transaction writes that occur in a short period of time.
Optimize the performance of the disk for the destination database. You can optimize disk partitioning or use SSDs to increase the disk read and write speeds.
Purchase a new DTS instance with a higher specification that can meet the requirements of the current business.