Dell PowerVault 720N, Command Reference Manual, Page: 260 / 606

9-8 Dell PowerVault 720N, 740N, and 760N System Administrator and Command Reference Guide
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For example, if you want to create two snapshots for the volume named vol1 each
week, you can set up a
cron
job on the administration host to run twice each week at
an appropriate time to execute the following
snap create
command:
rsh filer snap create vol1
filename
NOTE: The
snap create
command does not accept a snapshot name containing a
slash (/).
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It is important to understand the amount of disk space snapshots consume and the
amount of disk space they are likely to consume. The following sections explain how
to determine the amount of disk space used by snapshots.
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Suppose a snapshot contains a 1-MB file that hasn’t changed since the filer created
the snapshot. If that file is removed from the active file system, the snapshot then
consumes 1 MB of disk space.
The same version of that 1-MB file might be referenced by several snapshots:
hourly.0
,
hourly.1
, and
hourly.2
. If these snapshots all contain the 1-MB file that
hasn’t changed since the filer created those snapshots, only 1 MB of disk space is
consumed by the snapshots even though all three snapshots contain the file.
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To provide information about snapshot disk utilization, the
df
command on the filer
treats snapshots as a partition different from the active file system.
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Following is a partial sample
df
command output:
df
Filesystem kbytes used avail capacity
/vol/vol0 3000000 2000000 1000000 65%
/vol/vol0/.snapshot 1000000 500000 500000 50%