Database Startup fails with ORA-00444, ORA-07446

Problem Description
When I start my database my instace fails with ORA-00444 and ORA-07446 as follows.
SQL> startup
ORA-00444: background process "MMAN" failed while starting
ORA-07446: sdnfy: bad value '' for parameter .

Cause of The Problem
Database startup event is logged into alert log file. And alert log file is defined by the background_dump_dest parameter inside the initialization parameter. While starting up the instance if instance fail to write into the alert log file then instance crushes and fail to startup.

Solution of The Problem
There may be different scenario whenever oracle fails to write alert log contents. Suppose the partition reside alert log file is full. In that case delete/move unnecessary file from the alert log partition directory.

There may be the case the the directory defined by the background_dump_dest does not exist in the OS.

In both case you may also like to change the background_dump_dest location inside the pfile.

If you have spfile then,
1.create pfile='/oradata2/1.pfile' from spfile;
2.vi /oradata2/1.pfile
3.Modify the background_dump_dest to a valid location and in a patition where there is sufficient space available.
4.start the database isntance.
startup pfile= /oradata2/1.pfile';
5.create spfile again.
create spfile from pfile= /oradata2/1.pfile';