How can create a directory with 1GB size?

Do you mind having a file inside with 1GB size?

Yes, Infact I need to create a file with 10GB size. The mount point have more than 10GB space. Eventhen when I create Oracle DB Datafile it gives error.

So I need a way to create a directory with enough space and then create the file.

What is ulimit set to?
The directory size only relates to the number of entries that are in the directory.
IF you want a large directory, then write a script to create a few thousand empty files in the directory then delete the files.

It would take many, many thousands of empty files. This would devastate performance; and, by wasting a GB of space, it would reduce the probability of being able to create a large file in the same filesystem.

The real question here, is not how to create a large directory, but rather how to preallocate a large file.
The maximum size of an individual file is dependent upon the operating system and the file system type. This value may be further reduced by the value of ULIMIT, which can be set by the system administrator.
If you are using a system that does not support a 10gb file then you should consider creating an Oracle raw file system, or upgrading your current operating environment to one that will support larger files.

try command "mkfs"