Sybase 12.4.2 Selecting archive devices, Distribution of backup data, Disk backup requirements

Backing up your database

Distribution of backup data

BACKUP always makes a full backup of the Catalog Store on the first archive device, and then backs up the data from the IQ Store in parallel across all of the devices you specify. Blocks are not distributed evenly across archive media.

You may have more on one device than others, depending on the processing speed of individual threads.

Note The distribution of backup data is important because sets of files must be restored in the order in which they were backed up. See “Restoring in the correct order” on page 403 for more information.

Ensuring that your database is consistent

Although Backup does check that all necessary files are present before backing up your database, it does not check internal consistency. For a more thorough check, you can run the stored procedure sp_iqcheckdb before making a backup. See “Validating your database” on page 393 for details.

Selecting archive devices

You can back up any IQ database onto either disk or magnetic tape. Adaptive Server IQ supports backup and restore using multiple tape drives at near device speeds, or to multiple disks if disk striping is in use. You specify the backup device name in the archive_device parameter of the BACKUP command.

Disk backup requirements

Disk backups must go to a file system; raw disk is not supported as a backup medium. All disks on a RAID device are treated as a single device.

Tape backup requirements

If you regularly back up large databases, you should use DLT drives, if they are supported for your platform. In any case, Sybase recommends that you use multiple tape drives.

Adaptive Server IQ BACKUP can support the following tape drives:

•Digital Linear Tape (DLT) on UNIX systems

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