After a metadevice containing a file system is expanded (more space is added), if that metadevice contains a UFS, you need to "grow" the file system to recognize the added space.
If you use DiskSuite Tool to add additional space to a metadevice, you receive a growfs message automatically. If you use the command line interface, you must manually grow the file system with the growfs(1M) command.
An application, such as a database, that uses the raw device must have its own method to grow added space. DiskSuite does not provide this functionality.
The growfs(1M) command expands the file system, even while mounted.