snap create | delete name
snap rename oldname newname
snap sched [ weeks [ days [ hours[@list] ] ] ]
snap reserve [ percent ]
Snapshots are exported to all CIFS or NFS clients. They can be accessed from each directory in the file system. From any directory, a user can access the set of snapshots from a hidden sub-directory that appears to a CIFS client as ~snapsht and to an NFS client as .snapshot. These hidden sub-directories are special in that they can be accessed from every directory, but they only show up in directory listings at an NFS mount point or at the root of CIFS share.
The filer can have up to 20 different snapshots online at one time. Because of the copy-on-write technique used to update disk blocks, deleting a snapshot will generally not free as much space as its size would seem to indicate. Blocks in the snapshot may be referenced by other snapshots, or by the active file system, and thus may be unavailable for reuse even after the snapshot is deleted.
Automatic snapshots
Automatic snapshots can be scheduled to occur weekly, daily,
or hourly. Weekly snapshots are named weekly.N, where N is
"0" for the most recent snapshot, "1" for the next most
recent, and so on. Daily snapshots are named daily.N and
hourly snapshots hourly.N. Whenever a new snapshot of a
particular type is created and the number of existing
snapshots of that type exceeds the limit specified by the
sched option described below, then the oldest snapshot is
deleted and the existing ones are renamed. If, for example,
you specified that a maximum of 8 hourly snapshots were to
be saved using the sched command, then on the hour, hourly.7
would be deleted, hourly.0 would be renamed to hourly.1, and
so on.
snap create name
creates a snapshot with the specified name.
snap delete name
deletes the existing snapshot with the specified
name.
snap rename oldname newname
Renames a snapshop from oldname to newname. You
can use the snap rename command to move a
snapshot out of the way so that it won't be
deleted automatically.
snap sched [ weeks [ days [ hours [ @list ] ] ] ] sets the schedule for automatic snapshot creation. The first argument indicates how many weekly snapshots should be kept on-line, the second argument how many daily, and the third how many hourly. If an argument is left off, or set to zero, then no snapshot of the corresponding type is created. Daily snapshots are created at 24:00 of each day except Sunday, and weekly snapshots are created at 24:00 on Sunday. Only one snapshot is created at a time. If a weekly snapshot is being created, for instance, no daily or hourly snapshot will be created even if one would otherwise be scheduled. For example, the command
snap sched 2 6
indicates that two weekly snapshots and six daily snapshots should be kept on line. No hourly snapshots will be created. For snapshots created on the hour, an optional list of times can be included, indicating the hours on which snapshots should occur. For example the command
snap sched 2 6 8@8,12,16,20
indicates that in addition to the weekly and daily snapshots, eight hourly snapshots should be kept on line, and that they should be created at 8 am, 12 am, 4 pm, and 8 pm. Hours must be specified in 24-hour notation.
With no argument, snap sched prints the current snapshot schedule.
snap reserve [ percent ]
Sets the size of the snapshot reserve to per_cent.
With no argument, the snap reserve command
prints the percentage of disk space that is
reserved for snapshots. Reserve space can be
used only by snapshots and not by the active
file system.
The snap create, snap delete, and snap list commands can take 20 or 30 seconds on very large file systems.