Home > Storage > PowerMax and VMAX > Data Protection > Dell PowerMax 2500 and 8500: TimeFinder SnapVX Snapshots and Clones > Executive summary
Protecting application data has long been a priority for organizations because any data-integrity issue is a serious event. For almost as long, snapshots and clones have provided a reliable, predictable, and agile method for protecting applications and recovering data. These concerns were historically focused on accidental data corruption or data loss.
The increasing reliance on online information and transactions has also brought an increase in cyberattacks. Concern has shifted from accidental to malicious events. Data unavailability or loss effects financial assets and reputation. Scalable and resilient protection within storage arrays for quickly recovering data is more important than ever.
Dell TimeFinder software on Dell PowerMax 2500 and PowerMax 8500 storage arrays protects applications through two complementary products: TimeFinder/SnapVX and TimeFinder/Clone.
TimeFinder creates granular, highly scalable snapshots and clones for purposes such as backup and recovery from logical corruption, instantiation of test, development, and reporting environments. Host-accessible copies can be created by linking target volumes to SnapVX snapshots or creating a clone directly from the application source volumes. Snaps and clones can also be used as gold copies before major application updates.
SnapVX snapshots protect applications without the use of target volumes to capture changed data, which is referred to as snapshot deltas. Application volumes can have up to 1,024 SnapVX snapshots, and a single PowerMax storage system can have up to 65 million snapshots.
Snapshot deltas are automatically maintained at the storage back end using pointers to the relevant point-in-time images of the data. This SnapVX architecture is designed to provide cache and storage capacity efficiency as well as performance benefits through resource sharing and data deduplication.
Snapshots can be taken at regular intervals using Snapshot Policies, or on demand using Unisphere, Solutions Enabler Command Line Interface (CLI), or REST API scripting. Snapshots that are no longer required are automatically terminated. Manual and scripted snapshots can be set to automatically expire or can be terminated manually.
Applications cannot directly access snapshot data. When a snapshot is used for restoring point-in-time data, or is linked to target volumes, the original point-in-time data is preserved. As a result, the same snapshot can be used many times, over and over, without affecting its original data, until the snapshot is deleted. This functionality is especially useful when performing iterative patch testing because the same snapshot data can be used repeatedly until the test succeeds.
Similarly, a single snapshot can create many test environments using linked target volumes, and the original snapshot data is protected from the changes taking place in each environment.
Secure snapshots provide extra protection by preventing premature deletion of the snapshot until the specified retention period has expired along with other resiliency capabilities. Secure snaps support the same functionality with linked target as standard snapshots.
TimeFinder Clones create point-in-time replicas on target volumes that are immediately accessible to users. Using clones allows faster access to the target volumes without having to link them first, allowing simple creation of host-addressable replicas for a single, specific purpose. Like snapshots, clones are taken directly from the application volumes and are capacity efficient.
TimeFinder includes multiple complimentary functions that can work together to securely protect applications, recover data, and create independent copies that can be used in many ways. This document describes SnapVX and Clone in PowerMax 2500 and 8500 storage arrays running PowerMaxOS 10. Use cases for application protection, data recovery, and business continuity are described along with implementation guidelines and interoperability with other PowerMax features.
Date | Description |
July 2022 | Initial release |
Term | Definition |
TimeFinder session | Volumes that have SnapVX snapshots or clones are the source of a TimeFinder session. Clones and volumes linked to SnapVX snapshots are targets of a TimeFinder session. |
Source Volume | A host-addressable storage device that has SnapVX snapshots or Clones. |
Targetless Snapshot | A preserved, point-in-time image of a source volume that protects application data. |
Snapshot Delta | Versioned data preserved by a snapshot as production source data is updated. |
Snapshot policies | Automated, compliance-based schedules for creating snapshots. |
SnapSet | A group of consistent snapshots taken together. For example, a snapshot of a Storage Group that contains 10 volumes results in a SnapSet consisting of 10 consistent snapshots. For ease of management, a single snapshot is shown for the Storage Group with the snapshot name and date, based on the SnapSet. |
SnapSet ID | A system-generated number applied to snapshots in a SnapSet. |
Generation ID | A dynamic value used to identify snapshot versions. |
Linked Target Volume | A host-accessible point-in-time copy taken from a snapshot. |
SnapVX Link operation | An operation that applies the point-in-time image of a snapshot to a target volume. |
SnapVX Relink operation | An operation to refresh the point-in-time image on a linked target volume. Relinking to the same snapshot discards host updates on the target and resets the target to the point-in-time of the snapshot. Relinking to another snapshot also discards host updates on the target and resets the target to the point-in-time of the new snapshot. |
SnapVX Unlink operation | An operation that detaches a linked target from a snapshot. |
Clone | A host-accessible point-in-time copy taken from a source volume. |
Business Continuance Volume (BCV) | Optional device tag for linked targets and clones that can help identify copy volumes and report their capacity usage. The BCV tag is not required and does not affect any functionality. |
An array can have up to 65 million SnapVX snapshots. The following table provides TimeFinder session limits per source volume.
TimeFinder mode | Sessions per source volume |
Total TimeFinder sessions (combination of all modes) | 1,024 |
Automated SnapVX snapshots (Snapshot Policies, zDP) | 1,024 |
Manual SnapVX snapshots | 256 |
SnapVX linked targets | 1,024 |
Clones | 256 |
Dell Technologies and the authors of this document welcome your feedback on this document. Contact the Dell Technologies team by email.
Author: Michael Bresnahan
Note: For links to other documentation for this topic, see the PowerMax and VMAX Info Hub.