Sybase 12.4.2 Manuale Utente

CHAPTER 11    Backup and Data Recovery

The backup program passes vendor information to the third-party program 
automatically. When you request a third-party backup, it places this 
information in the backup header file, and writes the header file on the first tape 
or disk file actually created for each archive_device you specify.

The 

BACKUP

 command is the most reliable method you can use to back up IQ 

data. If you are careful to follow the procedures in this section, however, you 
can use system-level backups for an IQ database.

Do not use system-level backups for backing up your IQ database 

unless you follow these procedures. If you attempt to restore your IQ database 
files from a system-level backup without these safeguards in place, you are 
likely to cause data loss or corruption, either from activity in the database while 
the system-level backup occurred, or from missing files. 

Your IQ database must not be running during a system-level backup.

You must shut down your IQ database before starting the system-level backup. 
You must also ensure that no one starts the IQ database until the system-level 
backup is complete.

Ensuring that the 
database is shut down

The file protection of the .db file is read-only when the database is shut down 
cleanly, and set to read/write when the database is in use. If you are writing a 
script to perform backups, it is a good idea for the script to check the access 
mode of the file, to be sure that the database is shut down.

To ensure that a database remains shut down, the script can check the size of 
the .iqmsg file at the start and end of the script to make sure it has not changed. 
If the database was started while the script was running, the .iqmsg file will be 
bigger.