Solaris Volume Manager enables you to expand a volume by adding additional slices. You can use either the Enhanced Storage tool within the Solaris Management Console or the command line interface to add a slice to an existing volume.
You can expand a mounted or unmounted UFS file system that is contained within a volume without having to halt or back up your system. (Nevertheless, backing up your data is always a good idea.) After you expand the volume, use the growfs command to grow the file system.
After a file system has been expanded, it cannot be shrunk. Not shrinking the size of a file system is a UFS limitation. Similarly, after a Solaris Volume Manager partition has been increased in size, it cannot be reduced.
Applications and databases that use the raw volume must have their own method to “grow” the added space so that the application or database can recognize it. Solaris Volume Manager does not provide this capability.
You can expand the disk space in volumes in the following ways:
Adding one or more slices to a RAID 0 volume
Adding a slice or multiple slices to all submirrors of a RAID 1 volume
The growfs command expands a UFS file system without loss of service or data. However, write access to the volume is suspended while the growfs command is running. You can expand the file system to the size of the slice or the volume that contains the file system.
The file system can be expanded to use only part of the additional disk space by using the -s size option to the growfs command.
When you expand a mirror, space is added to the mirror's underlying submirrors. Likewise, when you expand a transactional volume, space is added to the master device. The growfs command is then run on the RAID 1 volume or the transactional volume, respectively. The general rule is that space is added to the underlying devices, and the growfs command is run on the top-level device.