Sybase 12.4.2 User Manual

CHAPTER 11    Backup and Data Recovery

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For stacker devices that hold multiple tape drives, all tapes for a given 
device must be the same size.

Sybase recommends that you always start a new tape for every backup. 

Before starting a backup to disk, Adaptive Server IQ first tests whether there is 
enough disk file space for the backup. For an operator-attended backup to disk, 
if there is not enough space, 

BACKUP

 prompts you to move some files from the 

disk before it writes any data. The backup does not start until you provide more 
disk space. 

Likewise, if you run out of space during an attended disk backup, 

BACKUP

 

closes all open backup files and waits until it detects that you have cleared 
some space. Then it restarts with new backup files. You can also stop the 
backup if you prefer.

By default, you must provide at least 8KB of free disk space before the backup 
resumes. 

Unattended backup cannot prompt you to provide more space. If enough space 
is not available, unattended backup fails. 

BACKUP

 treats size estimates 

differently for unattended backups. See “Unattended backup” for details.

For an operator-attended backup to tape, 

BACKUP

 simply begins the backup. If 

it runs out of room, you must mount additional tapes. 

Backups can be run concurrently with all other database operations with one 
exception: no metadata changes can occur while the Catalog Store is backed 
up. Be aware, however, that transactions that have not committed when you 
start a backup are not backed up. If a system or media failure occurs during 
backup, you cannot restore uncommitted transactions.

Once a backup is started, you cannot execute a 

CHECKPOINT 

command.

To back up an IQ database, use the following syntax:

BACKUP DATABASE
...[ CRC ON | OFF ]
...[ ATTENDED ON | OFF ]
...[ BLOCK FACTOR 

integer ]

...[ { FULL | INCREMENTAL | INCREMENTAL SINCE FULL } ]