Home > Storage > PowerMax and VMAX > Data Protection > Dell PowerMax 2500 and 8500: TimeFinder SnapVX Snapshots and Clones > Clones
Clones allow users to quickly replicate an application for immediate use by creating read/write copies independent of snapshots. Creating replicas that are not attached to snapshots reduces steps and resource usage.
Like SnapVX linked targets, clones in PowerMax 8500 and 2500 are also pointer-based and space-efficient. Source volume data is shared with the clone rather than being duplicated and copied, facilitating quick provisioning of capacity-efficient volumes.
Best practice: Clone volumes (or source volumes during restore) should be unmounted (not used by the host operating system or applications) before their data is refreshed. Perform a remount after the operation completes to ensure that the host operating system is not viewing cached file system data or keeping locks on data that is being changed at the storage level. The specific host operating system may require a host SCSI rescan if volumes were added to the host for the first time, and a reboot should be avoided.
Clones do not use a SnapVX snapshot. After clone data is modified, there is no preserved image that can be used for data recovery. Clones should not be used for application protection but are useful in situations where there is a requirement to restore modified target data directly back to the source. Think of clones as being the same as a SnapVX linked target but attached directly from the application Storage Group rather than being attached to a snapshot.
With Solutions Enabler, the target Storage Group and volumes must be created ahead of time. Unisphere and REST API have extra functionality to either select an existing Storage Group or create a Storage Group and volumes.
Best practice: Select Use Consistent for the clone to be dependent write consistent.
Single-level cascading a clone from a clone is supported. The first-level clone can have multiple second-level clones. A second-level clone can restore to the first-level clone.