Performance and tuning
When planning a deployment, we recommend reviewing these best practices for tuning BMC Helix Data Manager for optimal performance.
Oracle performance considerations
BMC Helix Data Manager is a bulk data extract-and-load tool. Technologies used in BMC Helix Data Manager allow for fast throughput, but your infrastructure impacts the performance you can expect.
Poor export performance on Oracle is almost always traced to your database not using in-row CLOBs. Do not rely on the ar.cfg setting. Instead, check the actual storage parameters. For more information, Minimum-and-recommended-specifications-for-BMC-Helix-Data-Manager-server.
If your database is performing poorly for general queries, it will probably impact the BMC Helix Data Manager extract and load times.
The key factors that impact export and import speeds are:
- Disk performance
- Oracle SGA/PGA sizing
- Network performance
- Archive log mode
- Replication
- Optimizer mode
Oracle SGA and PGA sizes determine how much system memory is available to Oracle for operations such as sorting, buffering, and parsing of queries. If these values are set too low, the database will generally perform badly when executing complex queries. Typically, databases perform well with production-sized SGA values. So, if your production database has a 20 GB SGA, the databases that you are using with BMC Helix Data Manager for data migration should have a similar value.
Disk performance
Disk performance affects BMC Helix Data Manager in these areas:
- Oracle read speed
- Oracle write speed
- File system read speed
- File system export speed
Each area impacts different BMC Helix Data Manager functions.
Column | Determining data to extract | Extracting data | Staging | Loading |
|---|---|---|---|---|
Oracle read speed | HIGH | HIGH | NONE | HIGH |
Oracle write speed | MEDIUM | NONE | HIGH | HIGH |
File system write speed | NONE | HIGH | NONE | NONE |
File system read speed | NONE | HIGH | HIGH | MEDIUM |
To determine Oracle related disk performance, examine the AWR reports.
To determine file system read and write performance, use the standard OS tools.
To determine the raw throughput on UNIX, use dd and hdparm. For more information, see https://www.cyberciti.biz/faq/howto-linux-unix-test-disk-performance-with-dd-command/
Disk input and output
Disk I/O is a major factor in data migration times. Use the fastest disks available for the database and BMC Helix Data Manager export/import directory.
Avoid remotely or network mounted disks. Writing large files over the network results in poor performance.
Shared import and export file system means no file transfer during data migration. This configuration is not possible in all scenarios, for example, when migrating to the cloud.