Sybase 12.4.2 manual 385

CHAPTER 11 Backup and Data Recovery

Backup file names for backup to disk

Positioning tape devices

Specifying tape devices on UNIX

BACKUP always assigns file names to disk backup files by appending a suffix to the archive_device name you specify. The suffix consists of “.” followed by a number that increases by one for each new file. For example, if you specify /iqback/mondayinc as the archive_device, the backup files are /iqback/mondayinc.1, /iqback/mondayinc.2, and so on. This convention allows you to store as large a backup as you need, while allowing you control over the file size; see the SIZE option for details. Your file system must support long file names to accommodate this convention.

You must make sure that the directory names you specify for the

archive_device exist. BACKUP does not create missing directories. If you try to start a backup in a directory that does not exist, the backup fails.

You should avoid using relative pathnames to specify the location of disk files. BACKUP interprets the pathname as relative to the location where the server was started, which you may not be able to identify with certainty when you do a backup. Also, if there is data in other directories along the path, you may not have enough room for the backup.

BACKUP does not position tapes for you. You must position the tape appropriately before starting your backup, and be sure that you do not overwrite any of the backup if you use a rewinding tape device. For these reasons, Sybase recommends you use a non-rewinding tape device. See the operating system documentation for your platform for appropriate naming conventions.

Here are examples of how you specify non-rewinding tape devices on UNIX platforms:

•On Sun Solaris platforms, insert the letter n for “no rewind” after the device name, for example, '/dev/rmt/0n'.

•On IBM AIX platforms, use a decimal point followed by a number that specifies the appropriate compression setting with rewind setting, for example, '/dev/rmt0.1'.

•On HP-UX platforms, use '0m' to specify the default tape mechanism and 'n' for “no rewind,” for example, '/dev/rmt/0mn'.

•On DEC UNIX platforms, put an n in front of the device name, for example, '/dev/nrmt0h'.

Warning! If you misspell a tape device name and write a name that is not a valid tape device on your system, BACKUP assumes it is a disk file.

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