The sybsystemdb database is used for the spt_values table and two-phase commits. Before ASE 12.5, this database was not required. The database is automatically created on the master device by the configuration utility.
Because this database may have a lot of activity and use a lot of log space, we strongly recommended that you create sybsystemdb on another device prior to upgrade or move it to another device after upgrade. This protects the master device in case the sybsystemdb log fills up.
If you will not use the features that require this database, you can keep it at the minimum size.