Introducing CA ARCserve Backup Agents and Options › Using Options › Tape Library Option › Tape RAID Option - Maximize Performance

Tape RAID Option - Maximize Performance

The Tape RAID Option offers significant performance benefits to your backup system by providing fault tolerance. You can monitor your system performance using the Windows Performance Monitor.

In order to maximize your performance, ensure the following:

• Your data bus can support the increased data flow.
• Your hard disk can support the increased data flow.

If you are not getting the performance benefits that you expect, check your system hardware. You may have to reconfigure or obtain new hardware in order to take maximum advantage of the Tape RAID capabilities. Verify that your hardware conforms to the requirements recommended by CA (see the Readme for specific hardware requirements).

• Use PCI/VLB or EISA adapters (for example, Adaptec AHA-2940).
• Connect your tape drives to dedicated controllers.
• When using high performance drives, you may need to limit the number of drives per adapter.
• Use proper media type (DLT IV vs. DLT III, DDS3 vs. DDS)
• Make sure that your drives are identical

For some types of drives, connecting more than one drive to the same board can significantly reduce performance.

There are other factors that could affect performance:

• The hard disk could be the cause of reduced performance. Make sure you have a hard disk that is fast enough to feed data to the RAID.
• One of the tape drives is slow due to bad media, etc.
• If another application accesses the same hard disk during backup, the performance will not be optimized because of hardware limitations.

The performance of a RAID device depends on the speed of the slowest drive attached. For example, in a 3-drive Level 0 RAID where drive 1=100 MB/min., drive 2=120 MB/min., and drive 3=120 MB/min., the total throughput will be 300 MB/min. Keep this information in mind when coordinating drives for RAID.

By increasing the buffer size, the performance of a backup or restore job can be improved. The optimum buffer size to set depends on a number of factors:

• The hardware being used (the tape drive, hard disk, and amount of memory in the system).
• The number of jobs that are running at that instance

You can modify the buffer size in the Properties window of Device Configuration. If Default is specified, CA ARCserve Backup will calculate an optimum value and use it. If Custom is specified, you can specify the buffer size. You can find out the best buffer size for you environment by trying a few of values. To determine the amount of memory you want to be used by one job, you should divide the total memory specified by the number of jobs that you will run simultaneously.