NetApp Snapshot technology is famous for its uniqueness and ease of use. For example, unlike most competing snapshot technologies, you can create a volume snapshot in seconds, regardless of the size of the volume. It is very efficient in storage space usage. And you can create hundreds of snapshot copies based on your needs. These excellent features are there for you in Data ONTAP 8.1 operating in cluster-mode.
The familiar 7-mode commands, such as snap reserve, snap sched and snap list, are still operational in cluster-mode. But cluster-mode has a new set of commands (see Fig. 1); which you can explore by simply typing the command (e.g., snap create) and hit return (see Fig. 2).
Figure 1: Cluster-mode snapshot commands
Figure 2: Cluster-mode snap create's usage
One thing I did observe is that the cluster-mode snapshot policy seems to take precedence over the 7-mode snap sched command. The default snapshot policy in cluster-mode is that the hourly, daily and weekly snapshot schedules are enabled, with the following frequency:
If you try to set snapshot schedule using the command snap sched <volume name> 0 0 0, meaning don’t take any scheduled snapshot, you will be surprised that this command is ignored; and hourly, daily and weekly snapshot copies are taken.
There are several ways to change the default snapshot policy in cluster-mode. Here are some examples:
a) Use the snap policy modify command to disable the policy
b) Under the scope of snapshot policy, use add-schedule, modify-schedule, or remove-schedule to change it to your liking (see Fig. 3)
c) You can also use snap policy create to create new snapshot policy
Figure 3: Cluster-mode snapshot policy commands
In summary, the 7-mode commands, by and large, are still valid for snapshot management. But be aware of the new cluster-mode snapshot policy which may take precedence.