BESR 8.5 Backup Performance

NOTE: This document includes a downloadable zip that is designed for BESR 8.5.  For information on performance in BESR 8.0 please see  http://support.veritas.com/docs/308279 .

BESR 8.5 has been configured to provide good performance for all users. Typically when a backup is saved locally, such as to an external (USB/Firewire) hard drive or to an internal hard drive, different from the drive containing the source volume, performance is very good. Performance issues are more common when the recovery point is being saved to a network destination, such as a NAS box or Windows share. Some network destinations exhibit very poor performance with very large files (more than 30 GB in size). An easy way to resolve this problem is to store the recovery point as a bunch of small files rather than a single big file. This is called spanning. Backup jobs can be configured to span by bringing up the Advanced Options dialog from the Options dialog of the Define Backup Wizard. The first check box on this dialog, "Divide into smaller files to simplify archiving" can be used to specify a span size. After checking the box, select 5078 from the "File size (MB)" drop down list. For very large recovery points, those resulting in files over 100 GB, performance is often two and sometimes as much as six times faster with this setting.

Beyond changing to use spanned recovery points, the default performance settings are recommended except in situations where the user's backup window must be highly optimized. To facilitate performance tuning in these limited situations, we have included a set of registry (.reg) files that modify the default performance settings. In some cases the alternate settings may improve performance. Alternate performance settings generally have the most impact when the recovery point (V2i file) is being saved to a network share. When the recovery point is being saved to a second internal hard drive or to an external USB or Firewire hard drive, the default settings will generally provide the best results.

BESR backup performance across a network is affected by both the configuration of the machine running the backup and the network share where the backup is being created. The optimal settings for machine A backing up to network share N may not be the optimal settings when A backs up to network share M . If machine B is configured identically to machine A (same motherboard, NIC, OS version and patches), the settings that are optimal for A will generally also be optimal for B. However, if B is different than A, the optimal settings for A to network share N may be actually behave poorly for machine B to this same destination.

BESR performance is also affected by the compression level that is selected. The optimal performance settings may be different for different compression levels. On most systems with optimal performance settings, medium compression will provide the fastest performance, but it is generally very close in time to Standard compression.

The easiest way to test performance is to create a BESR job that creates stand-alone, independent full recovery points. Run this job once to find out how long a backup takes with the default settings. After the backup completes, delete the backup file so that the next backup can be saved to the same location. Next, double click on one of the performance .reg files to load that file's settings. Run the backup job again to see if there are any differences. Jobs can show slight variations so performance differences of less than 10% or less than 1 minute likely aren't meaningful. Typically, the best settings will be 2-3 times as fast as other settings. On many systems, multiple .reg files will provide essentially the same performance.

The zip available in this technote contains a total of eight files.  Four files are designed for an x86 system and the other four files are designed for a 64 bit system.  

NOTE: Only use the x86 registry files on 32 bit operating systems, and x64 registry files on a 64 bit operating systems.

AltPerformance1-x64.reg: These settings frequently improve the performance of servers saving recovery points to a network share, making the backup 2-3 times faster. However, for some machines, most commonly laptops, they result in a slowdown that is 10-20 times slower than the default settings. Many machines will see no significant difference in performance with these settings.

AltPerformance2.reg: These are the default settings on single-processor, single-core computers. They are also the default setting used when the recovery point is not being compressed or encrypted. On a multi-processor and/or multi-core system, these settings restrict the compression and encryption to run on a single CPU. This will almost always result in slower performance when high compression is used. In some cases it may improve performance for Standard and Medium compression.

AltPerformance3.reg: This is a combination of the settings in AltPerformance1 and AltPerformance2. For single-processor, single-core systems or when the recovery point is not compressed or encrypted, these settings will be identical to AltPerformance1.

DefaultPerformance.reg: This file will restore BESR to its default performance settings.