Interesting post on max_dump_file_size

From Oracle Database reference:

MAX_DUMP_FILE_SIZE

Property	Description
Parameter type	String
Syntax	MAX_DUMP_FILE_SIZE = { integer [K | M] | UNLIMITED }
Default value	UNLIMITED
Modifiable	ALTER SESSION, ALTER SYSTEM
Range of values	0 to unlimited, or UNLIMITED
Basic	No

MAX_DUMP_FILE_SIZE specifies the maximum size of trace files (excluding the alert file). Change this limit if you are concerned that trace files may use too much space.

• A numerical value for MAX_DUMP_FILE_SIZE specifies the maximum size in operating system blocks.

• A number followed by a K or M suffix specifies the file size in kilobytes or megabytes.

• The special value string UNLIMITED means that there is no upper limit on trace file size. Thus, dump files can be as large as the operating system permits.

I found a very interesting post on Doug's Oracle blog about issues faced while setting this parameter.