VERITAS File SystemÖ 3.5 (HP OnlineJFS/JFS3.5) AdministratorÆs Guide (December 2002)

Chapter 5
Storage Checkpoints
Storage Checkpoint Administration
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# echo "goodbye" > /mnt0/file
Step 5. Examine the content of the original file and the Storage Checkpoint file. The original file contains
the latest data while the Storage Checkpoint file still contains the data at the time of the Storage
Checkpoint creation:
# cat /mnt0/file
goodbye
# cat /mnt0@5_30pm/file
hello, world
Step 6. Unmount the Storage Checkpoint, convert the Storage Checkpoint to a nodata Storage Checkpoint,
and mount the Storage Checkpoint again.
# umount /mnt0@5_30pm
# fsckptadm -s set nodata ckpt@5_30pm /mnt0
# mount -F vxfs -o ckpt=ckpt@5_30pm \
/dev/vx/dsk/test0:ckpt@5_30pm /mnt0@5_30pm
Step 7. Examine the content of both files. The original file must contain the latest data:
# cat /mnt0/file
goodbye
You can traverse and read the directories of the nodata Storage Checkpoint; however, the files
contain no data, only markers to indicate which block of the file has been changed since the Storage
Checkpoint was created:
# ls -l /mnt0@5_30pm/file
-rw-r--r-- 1 root other 9 Jul 13 17:13 /mnt0@5_30pm/file
# cat /mnt0@5_30pm/file
cat: read error: No such file or directory
Conversion with Multiple Storage Checkpoints
The following example highlights the conversion of data Storage Checkpoints to nodata Storage Checkpoints,
particularly when dealing with older Storage Checkpoints on the same file system:
Step 1. Create a file system and mount it on /mnt0:
# mkfs -F vxfs /dev/vx/rdsk/test0
version 4 layout
4194304 sectors, 2097152 blocks of size 1024,
log size 1024 blocks
unlimited inodes, largefiles not supported
2097152 data blocks, 2095536 free data blocks
64 allocation units of 32768 blocks, 32768 data blocks
# mount -F vxfs /dev/vx/dsk/test0 /mnt0
Step 2. Create four data Storage Checkpoints on this file system, note the order of creation, and list them:
# fsckptadm create oldest /mnt0
# fsckptadm create older /mnt0
# fsckptadm create old /mnt0
# fsckptadm create latest /mnt0
# fsckptadm list /mnt0
/mnt0
latest:
ctime =Mon Oct 16 11:56:55 2001
mtime =Mon Oct 16 11:56:55 2001