Types of Storage Checkpoints

You can create the following types of Storage Checkpoints:

• Data Storage Checkpoints
• Nodata Storage Checkpoints
• Removable Storage Checkpoints
• Non-Mountable Storage Checkpoints

Data Storage Checkpoints

A data Storage Checkpoint is a complete image of the file system at the time the Storage Checkpoint is created. This type of Storage Checkpoint contains the file system metadata and file data blocks. You can mount, access, and write to a data Storage Checkpoint just as you would to a file system. Data Storage Checkpoints are useful for backup applications that require a consistent and stable image of an active file system. Data Storage Checkpoints introduce some overhead to the system and to the application performing the write operation. For best results, limit the life of data Storage Checkpoints to minimize the impact on system resources. See Difference Between a Data and a Nodata Storage Checkpoint.

Nodata Storage Checkpoints

A nodata Storage Checkpoint only contains file system metadata---no file data blocks. As the original file system changes, the nodata Storage Checkpoint records the location of every changed block. Nodata Storage Checkpoints use minimal system resources and have little impact on the performance of the file system because the data itself does not have to be copied. See Difference Between a Data and a Nodata Storage Checkpoint.

Removable Storage Checkpoints

A removable Storage Checkpoint can "self-destruct" under certain conditions when the file system runs out of space (see Space Management Considerations for more information). After encountering certain out-of-space (ENOSPC) conditions, the kernel removes Storage Checkpoints to free up space for the application to continue running on the file system. In almost all situations, you should create Storage Checkpoints with the removable attribute.

Non-Mountable Storage Checkpoints

A non-mountable Storage Checkpoint cannot be mounted. You can use this type of Storage Checkpoint as a security feature which prevents other applications from accessing the Storage Checkpoint and modifying it.