I have some questions about backup. I hope someone can help me understand some of the different backup types.
In the documentation (SQL Anywhere 16) it is stated that:
"Typically, a backup uses a combination of full and incremental backups. The frequency of each backup type depends on the type of data that you are protecting. You should also validate your backups to ensure that they can be used for recovery."
But when I am looking at the different types of backup and recovery this makes me wonder...
both on image and archive backup the documentation says (Database rcovery)
"You must not have any incremental backups of the transaction log that need to be applied as part of the recovery process."
ok then I would interpret this that you can not then apply an incremental backup, so you can not mix incremental backups with image or archive backup
So then it is "only" the dbbackup that you can use both full and incremental backup?
Then if you use live backup and the secondary computer loses contact with the "main" computer what happends (when the main computer and the database there is online, not down)? What is the proper thing to do, so you do not "break" anything in this situation?
Step 1: Ignore any and all discussions of "Archive Backup". Unless you use tape drives or other archaic storage media, you will never be creating or restoring from an archive backup.
Step 2: Ignore any and all discussions of backup and restore based on simple operating system COPY commands. Those operations require you to shut down the database before creating what is called an "offline backup"... it is a perfectly viable technique, but not really useful in most production environments.
Step 3: For the time being, ignore discussions of "Live Backup" until you understand the basics of image backups, both full and incremental log versions thereof. Live backup is a sophisticated failover technique that isn't really a substitute for local backups, it's more of an early version of High Availability mirror databases... which itself is not a substitute for backups.
Step 4: Ignore the exhortation "You must not have any incremental backups of the transaction log that need to be applied as part of the recovery process." It appears in exactly three locations in the Help; two are discussions of Archive Backups (see Step 1 above) and the third is a discussion of offline COPY backups (see Step 2 above).
Step 5: Study and understand full and incremental image backups. I suggest this article: Demonstrating Backup, Validation and Restore
...it may seem daunting at first glance, but it is A LOT LESS DAUNTING than trying to recover a database in an emergency without a thorough understanding of how things work.
See also: Backup is easy, recovery is hard...