Strategies for creating a Snapshot schedule

Following are some strategies for scheduling and retaining Snapshot copies:

If users rarely lose files or typically notice lost files right away, use the default Snapshot schedule. This schedule creates no weekly Snapshot copy; it creates a Snapshot copy every night and keeps two; and it creates hourly Snapshot copies at 8 a.m., noon, 4 p.m., and 8 p.m, and keeps six. Following is the default Snapshot copy command: snap sched volume_name 0 2 6@8,12,16,20
If users commonly lose files or do not typically notice lost files right away, delete the Snapshot copies less often than you would if you used the default schedule.

Following is the recommended Snapshot schedule for this situation. It keeps two weekly Snapshot copies, six nightly Snapshot copies, and eight hourly Snapshot copies: snap sched vol1 2 6 8@8,12,16,20

On many systems, only 5 or 10 percent of the data changes each week, so the Snapshot schedule of six nightly and two weekly Snapshot copies consumes 10 to 20 percent of disk space. Considering the benefits of Snapshot copies, it is worthwhile to reserve this amount of disk space for Snapshot copies.
You can create different Snapshot schedules for different volumes on a storage system. On a very active volume, schedule Snapshot copies every hour and keep them for just a few hours, or turn off Snapshot copies. For example, the following schedule creates a Snapshot copy every hour and keeps the last three: snap sched vol2 0 0 3
This schedule does not consume much disk space, and it lets users recover files in recent Snapshot copies as long as they notice their mistake within a couple of hours.
When you create a new volume, the new volume inherits the Snapshot schedule from the root volume. After you use the volume for a while, check how much disk space the Snapshot copies consume and how often users need to recover lost files, and then adjust the schedule as necessary.

Parent topic: Creating Snapshot schedules

Related concepts

What Snapshot disk consumption is