Database and backup restrictions

Before you can start replicating data from a Sybase database, you must follow certain database and backup restrictions on each database you want the CDC Replication Engine for Sybase databases to connect to.

These restrictions apply only if the Sybase database is used as a replication source. The restrictions arise because CDC Replication must read the backup (archive) logs in addition to reading the online (live) log.

Database restrictions

When you use a Sybase database, consider the following restrictions.

Ensure the truncate log option on checkpoint is disabled: If the truncate log option is enabled, the database log will be truncated automatically without backup every time a database checkpoint is performed.
Never run truncate_only operations: Running dump transaction with the truncate_only option deletes inactive transactions from the log without creating a backup.
Use only data or log segments, not a combination: If a database has mixed segments, log backup is not allowed and only full database backups can be performed.

Backup restrictions

CDC Replication uses your existing Sybase backup strategy to maintain transaction logs and backup archive files.

You should consider the following backup restrictions:

All backup archive files must be in one directory: You will have to specify the archive log directory when you configure CDC Replication.; Do not place the archive logs in the same directory as your online logs and do not place the archive logs for more than one Sybase database in the same directory.
Backup files must be locally accessible: Do not back up with striping to multiple disks, to tapes, or to remote servers.
Use only decompressed backup files: Do no execute compressed backups. Only decompressed backup files can be read.