Managing Snapshot copies
This chapter describes how to manage Snapshot copies using SnapDrive.
- What a Snapshot copy is
A Snapshot copy is a frozen, read-only image of a traditional volume, a FlexVol volume, or an aggregate that captures the state of the file system at a point in time.
- Reasons for creating Snapshot copies
You use SnapDrive to ensure that you create consistent Snapshot copies in the event you need to restore a LUN from that copy.
- Restrictions on Snapshot copy creation
You must keep in mind some restrictions for creating Snapshot copies.
- Creating a Snapshot copy
You should always use SnapDrive to create Snapshot copies of LUNs to ensure that Snapshot copies are consistent.
- Scheduling Snapshot copies
Create a Snapshot copy schedule to ensure that SnapDrive creates Snapshot copies at intervals appropriate to your environment.
- About using FlexClone volumes in SnapDrive
By default, if the prerequisites are met, SnapDrive uses FlexClone technology to connect to LUNs in a Snapshot copy.
- Snapshot copy cautions
Keep the following points in mind when working with Snapshot copies and LUNs that are backed up by a Snapshot copy:
- Connecting to a LUN in a Snapshot copy
You can connect to a LUN in a Snapshot copy using either a FlexClone volume or a read/write connection to a LUN in a Snapshot copy depending on what version of Data ONTAP you have installed on your storage system.
- About restoring LUNs from Snapshot copies
When you restore a LUN from a Snapshot copy, the LUN reverts to the state it was in when the Snapshot copy was made: the restore operation overwrites all data written to the LUN since the Snapshot copy was made.
- Deleting a Snapshot copy
You should delete older SnapDrive Snapshot copies to keep the number of stored Snapshot copies less than the hard limit of 255 for Data ONTAP and to free space on the storage system volume. Be sure to delete old Snapshot copies before the hard limit is reached; otherwise, subsequent Snapshot copies could fail. Even before the Snapshot copy limit is reached, a Snapshot copy fails if insufficient reserved space for it remains on the disk.
- Overview of archiving and restoring Snapshot copies
A good way to protect and retain data is to archive the SnapDrive Snapshot copies of the LUNs to offline, offsite media, such as near-line technology or alternate storage methods.
