Veritas NetBackup™ for Microsoft SQL Server Administrator's Guide

Number of backup stripes

This option divides the backup operation into multiple concurrent streams. A stream corresponds to a job in the activity monitor. For example, if the value is 3, each database is backed up using three jobs. This configuration applies in any situation in which SQL Server dumps data faster than your tape drive is capable of writing.

The default value for this option is 1. Range is 1-32.

See Configuring multistriped backups of SQL Server.

Client buffers per stripe

(Stream-based backups only) This option affects buffer space availability. NetBackup uses this parameter to decide how many buffers to allocate for reading or writing each data stream during a backup operation. By allocating a greater number of buffers, you can affect how quickly NetBackup can send data to the NetBackup master server.

The default value for this option is 2, which allows double buffering. You may get slightly better performance by increasing this value to a higher value. Range is 1-32.

Maximum transfer size

(Stream-based backups only) This option is the buffer size used by SQL Server for reading and writing backup images. Generally, you can get better SQL Server performance by using a larger value. This option can be set for each backup operation. Calculated as 64 KB * 2^MAX_TRANSFER_SIZE. It ranges in size from 64 KB to 4 MB. The default is 4 MB.

Backup block size

This option applies to stream-based backups only. Sets the incremental size that SQL Server uses for reading and writing backup images and can be set for each backup operation. Calculated as 512 bytes * 2^BLOCK_SIZE. The value for this option ranges from 0.5 KB to 64 KB. The default is 64 KB.

Parallel backup operations

This option is the number of backup operations to start simultaneously, per database instance. Range is 1-32. The default is 1.

You may need to configure other options when you configure two or more parallel backup operations.

See Configuring the number of jobs allowed for backup operations.

Microsoft SQL Server checksum

Choose one of the following options for SQL Server backup checksums:

Use Microsoft SQL Server compression

Enable this option to use SQL Server to compress the backup image. If you enable SQL Server compression, do not enable NetBackup compression.

SQL Server compression is not supported for snapshot backups.

Skip unavailable (offline, restoring, etc.) databases

NetBackup skips any database with a status that prevents NetBackup from successfully backing up the database. These statuses include offline, restoring, recovering, and emergency mode, etc.

NetBackup skips the backup of the unavailable database, but continues with the backup of the other databases that the policy includes. The backup completes with a status 0 and the job details indicate that the database was skipped.

See Schedule backup types for SQL Server Intelligent Policies.

Copy-only backup

This option allows SQL Server to create an out-of-band backup so that it does not interfere with the normal backup sequence. The default value is unchecked except for full database Instant Recovery backups.

See Using copy-only snapshot backups to affect how differentials are based.

Skip read-only file groups

This option excludes any filegroups that are read-only from the backup. The resulting backup is a partial image because the image does not contain all filegroups. The partial image contains data from the read-write filegroups and data from the primary filegroup.

This option applies only to the Whole database backup selection.

See Backing up read-write filegroups (SQL Server Intelligent Policies).

Convert differential backups to full (when no full exists)

If no previous full backup exists for the database or filegroup, then NetBackup converts a differential backup to a full backup.

The agent checks to determine if a full backup exists for each database. If no previous full backup exists, a differential backup is converted to a full as follows:

Note: NetBackup only converts a differential backup if a full backup was never performed on the database or filegroup. If a full backup does not exist in the NetBackup catalog but SQL Server detects an existing full LSN, NetBackup performs a differential backup and not a full. In this situation, you can restore the full backup with native tools and any differentials with the NetBackup MS SQL Client. Or, if you expired the backup in NetBackup, you can import the full backups into the NetBackup catalog. Then you can restore both the full and the differential backups with the NetBackup MS SQL Client.

Truncate logs after backup

This option backs up the transaction log and removes the inactive part of the transaction log. This option is enabled by default.

Convert log backups to full (when no full exists)

If no previous full backup exists for the database, then NetBackup converts a transaction backup to a full backup.

This option also detects if a full recovery database was switched to the simple recovery model and back to the full recovery model. In this scenario, the log chain is broken and SQL Server requires a differential backup before a subsequent log backup can be created. If NetBackup detects this situation, the backup is converted to a differential database backup.

Note: NetBackup only converts a transaction log backup if a full backup was never performed on the database. If a full backup does not exist in the NetBackup catalog but SQL Server detects an existing full LSN, NetBackup performs a transaction log backup and not a full. In this situation, you can restore the full backup with native tools and any differentials and log backups with the NetBackup MS SQL Client. Or, if the backup was expired by NetBackup, you can import the full backups into the NetBackup catalog. Then you can restore the full, differential, and log backups with the NetBackup MS SQL Client.