Planning SnapVault backup schedule and Snapshot copy retention

It is important to plan the SnapVault backup schedule and number of Snapshot copies to be retained.

Before You Begin

Before you start SnapVault configuration, use a table to plan how many Snapshot copies you want per volume, when you want them updated, and how many of each you want to keep.

For example:

Hourly (periodically throughout the day)
Does the data change often enough throughout the day to make it worthwhile to create a Snapshot copy every hour, every two hours, or every four hours?
Nightly
Do you want to create a Snapshot copy every night or just workday nights?
Weekly
How many weekly Snapshot copies is it useful to keep?

On storage-based primary systems and SnapVault secondary storage systems, the data to be backed up is captured and preserved in Snapshot copies.

Steps

On the Data ONTAP primary storage systems, plan the intervals at which to create SnapVault Snapshot copies of your primary system qtrees. The maximum frequency at which you can take Snapshot copies is 1 hour.
Note: On primary storage platforms not running Data ONTAP, Snapshot copy planning and creation does not apply. For more information, see the Open Systems SnapVault documentation.
On the SnapVault secondary storage system, plan the intervals at which you want to update the secondary system qtrees with data transferred from primary storage platforms, and create SnapVault Snapshot copies to retain that information.
Plan how to limit the combined total of Snapshot copies retained on any one volume of the SnapVault secondary storage system to 251 or fewer.
Attention: The combined total of Snapshot copies retained on each volume of the SnapVault secondary storage system cannot exceed 251. If the number of Snapshot copies per volume limit is reached and the old Snapshot copies are not deleted, SnapVault will not create new Snapshot copies on that volume.

Example

In this example, the user is supposed to have 12 qtrees on the secondary storage system volume.

Snapshot intervals	Primary storage: when created	Primary storage: Snapshot copies retained	Secondary storage: when created	Secondary storage: Snapshot copies retained
weekly	sat @19	4	sat @21	8
nightly	mon-fri @19	10	mon-fri @20	60
hourly	@7-18	11	@8-19	120
Total	n/a	21	n/a	188

On the secondary storage system, the user schedules the following:

A weekly update every Saturday at 9:00 p.m. and keeps 8 of them
A daily update every Monday through Friday at 8:00 p.m and keeps 60 of them
An hourly update every hour from 8:00 a.m. to 7:00 p.m. and keeps 120 of them

The result in this example is that 188 Snapshot copies are being kept in the SnapVault secondary storage system volume.

The limit on Snapshot copies per volume is 251, so the 188 Snapshot copies scheduled in this example do not exceed the volume limit.

If you need to retain more than 251 Snapshot copies on the SnapVault secondary storage system, you can configure additional volumes on the secondary storage system. Each additional volume can support 251 additional Snapshot copies.

Parent topic: Planning SnapVault backups