In versions 11.5.x and 11.9.x, the sybsystemdb database was required only for servers using two-phase commit transactions. Beginning with version 12.0, all servers must have a sybsystemdb database. Adaptive Server uses this database for tracking transactions and during recovery. In addition, it is used for applications using two-phase commit and distributed transaction management (DTM).
If you have a sybsystemdb and the database is at least 4MB, you do not need to make any changes. If the database is smaller than 4MB, increase the size with alter database.
If you do not have a sybsystemdb, and will not be using two-phase commit or DTM applications, create a sybsystemdb with a minimum of 4MB.
If you will be using two-phase commit or DTM, you can either:
Create a minimum-sized sybsystemdb for upgrade and expand it later, or
Create a sybsystemdb of 5 to 20MB, depending on your expected usage. Approximately 25 percent of the database should be data storage, and 75 percent should be log storage.