The fsadm -S shared, du, and df commands report different values for the size of a FileSnap. The fsadm -S shared command displays this size as the "logical size," which is the logical space consumed, in kilobytes, and accounts for both exclusive blocks and shared blocks. This value represents the actual disk space needed if the file system did not have any shared blocks. The value from the fsadm -S shared command differs from the output of du -sk command since the du command does not track the blocks consumed by VxFS structural files. As a result, the output of the du -sk command is less than the logical size output reported by the fsadm -S shared command.
The following examples show output from the fsadm -S shared, du, and df commands:
# mkfs -t vxfs -o version=9 /dev/vx/rdsk/dg/vol3 version 9 layout 104857600 sectors, 52428800 blocks of size 1024, log size 65536 blocks rcq size 4096 blocks largefiles supported # mount -t vxfs /dev/vx/dsk/dg/vol3 /mnt # df -k /mnt Filesystem 1K-blocks Used Available Use% Mounted on /dev/vx/dsk/dg1/vol3 52428800 83590 49073642 1% /mnt # /opt/VRTS/bin/fsadm -S shared /mnt Mountpoint Size(KB) Available(KB) Used(KB) Logical_Size(KB) Shared /mnt 52428800 49073642 83590 83590 0% # du -sk /mnt 0 /mnt # dd if=/dev/zero of=/mnt/foo bs=1024 count=10 10+0 records in 10+0 records out 10240 bytes (10 kB) copied, 0.018901 seconds, 542 kB/s # vxfilesnap /mnt/foo /mnt/foo.snap # df -k /mnt Filesystem 1K-blocks Used Available Use% Mounted on /dev/vx/dsk/dg1/vol3 52428800 83600 49073632 1% /mnt # /opt/VRTS/bin/fsadm -S shared /mnt Mountpoint Size(KB) Available(KB) Used(KB) Logical_Size(KB) Shared /mnt 52428800 49073632 83600 83610 0% # du -sk /mnt 20 /mnt