The ability and method to access data within a snapshot of a resource directly depends on the resource type. For snapshots created on volumes, volume groups, or thin clones, direct access to the data within the snapshot is not allowed. Instead, a thin clone can be created and mapped to a host to provide access to the data. Thin clones are described in the section Thin clone overview.
For file system and file system thin clone snapshots, the method of access directly depends on the type of snapshot that was taken. File systems and thin clones support Protocol (Read-Only) snapshots and Snapshot (Read-Only) snapshots. Both snapshot types allow read-only access to the point-in-time copy of the data within the snapshot, but the method to access the protocol and Snapshot-type snapshots varies.
A protocol snapshot is not shared by default. To gain read-only access to the data within a protocol snapshot, export the snapshot as an SMB share or NFS export. This process can be completed manually, or it can be scripted. When a share/export is created, access is provided through the same NAS server as the parent resource. Protocol snapshots are the default type for snapshots that are created by a snapshot rule, or when a snapshot is manually created. Creating and modifying a snapshot rule is covered in the section Snapshot rules.
Figure 16 shows the Snapshots tab on the Protection tab within the properties of a file system. This example focuses on the file system named Engineering. It shows the snapshots that are created on this resource, along with other information such as the Access Type, Name, Type, Creation Time, and Expiration Time. To access any of the protocol snapshots, export them as an SMB share, NFS export, or both.
To share access to the protocol snapshot, go to either the SMB Shares or NFS Exports tab on the File Systems page and click Create. In Figure 17, the example creates an SMB share that is based on a snapshot that is created on the Engineering file system.
Select the file system and click Next, and the Select Snapshot step is shown. An example of this window is shown in Figure 18. The Select Snapshot step is optional and is only used when sharing a snapshot of a file system. If a snapshot is not being shared, skip this step by clicking Next. On this step, all protocol snapshots on the file system are shown. From here, select the chosen snapshot and click Next. After completing the remainder of the share creation workflow, access the snapshot through the share created.
For Snapshot-type snapshots, access is always available through SMB or NFS, depending on how the parent file system is shared. Having access to a Snapshot-type snapshot allows the user to easily access and restore previous versions of one or more files directly from the share at any time. For SMB, viewing the Previous Versions tab within the properties window of a folder in a file system brings up Snapshot-type snapshots on the resource. Navigating into the snapshot allows access to previous version of the data. For NFS, accessing the hidden Snapshot folder in the file system brings up access to the snapshots. This snapshot type is always mounted and counts towards the maximum number of mounted file systems, Snapshots, and mounted protocol snapshots. See the document Dell PowerStore Support Matrix on for more information about limits.
Figure 19 shows an example of the SMB and NFS access methods to Snapshot-type snapshots. The top window shows the properties of the Test folder within the file system, and the Previous Versions tab is selected. Two snapshots are listed which provide access to the data they contain at those points in time. On the bottom, a mounted NFS export is opened and the Snapshot folder is accessed to view the available snapshots on the file system.