Veritas Storage Foundation 5.1 SP1 Advanced Features Administrator"s Guide (5900-1503, April 2011)

Converting a data Storage Checkpoint to a nodata Storage Checkpoint
A nodata Storage Checkpoint does not contain actual file data. Instead, this type
of Storage Checkpoint contains a collection of markers indicating the location of
all the changed blocks since the Storage Checkpoint was created.
See “Types of Storage Checkpoints” on page 272.
You can use either the synchronous or asynchronous method to convert a data
Storage Checkpoint to a nodata Storage Checkpoint; the asynchronous method
is the default method. In a synchronous conversion, fsckptadm waits for all files
to undergo the conversion process to “nodata" status before completing the
operation. In an asynchronous conversion, fsckptadm returns immediately and
marks the Storage Checkpoint as a nodata Storage Checkpoint even though the
Storage Checkpoint's data blocks are not immediately returned to the pool of free
blocks in the file system. The Storage Checkpoint deallocates all of its file data
blocks in the background and eventually returns them to the pool of free blocks
in the file system.
If all of the older Storage Checkpoints in a file system are nodata Storage
Checkpoints, use the synchronous method to convert a data Storage Checkpoint
to a nodata Storage Checkpoint. If an older data Storage Checkpoint exists in the
file system, use the asynchronous method to mark the Storage Checkpoint you
want to convert for a delayed conversion. In this case, the actual conversion will
continue to be delayed until the Storage Checkpoint becomes the oldest Storage
Checkpoint in the file system, or all of the older Storage Checkpoints have been
converted to nodata Storage Checkpoints.
Note: You cannot convert a nodata Storage Checkpoint to a data Storage
Checkpoint because a nodata Storage Checkpoint only keeps track of the location
of block changes and does not save the content of file data blocks.
Showing the difference between a data and a nodata Storage
Checkpoint
The following example shows the difference between data Storage Checkpoints
and nodata Storage Checkpoints.
Note: A nodata Storage Checkpoint does not contain actual file data.
279Administering Storage Checkpoints
Storage Checkpoint administration