If you cannot make a transaction dump on a database, sp_tran_dumable_status displays the reasons the dump is not possible.
sp_tran_dumpable_status [database_name]
name of the database you are researching.
Describes the reasons you cannot currently make a transaction dump on sybsystemprocs:
sp_tran_dumpable_status sybsystemprocs
bit description ----------- ---------------------------- 2 Log is not on its own device 8 Trunc log on ckpt is set 32 Dump tran with truncate_only 64 Database is new or upgraded