VERITAS File System 4.1 Administrator's Guide

Storage Checkpoints
Storage Checkpoint Administration
Chapter 5102
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 Chekpoints, 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
Difference Between a Data and a Nodata Storage Checkpoint
The following example shows the difference between data Storage Checkpoints and nodata
Storage Checkpoints:
1. Create a file system and mount it on /mnt0:
# mkfs -F vxfs /dev/vx/rdsk/dg1/test0
version 6 layout
1024000 sectors, 512000 blocks of size 1024, log size 1024
blocks, largefiles supported
# mount -F vxfs /dev/vx/dsk/dg1/test0 /mnt0
2. Create a small file with a known content. Create a Storage Checkpoint and mount it on
/mnt0@5_30pm:
# echo "hello, world" > /mnt0/file
# fsckptadm create ckpt@5_30pm /mnt0
# mkdir /mnt0@5_30pm
# mount -F vxfs -o ckpt=ckpt@5_30pm \
/dev/vx/dsk/dg1/test0:ckpt@5_30pm /mnt0@5_30pm
3. Examine the content of the original file and the Storage Checkpoint file:
# cat /mnt0/file