The ME5 storage system can create multiple point-in-time snapshots of virtual volumes. This section discusses snapshots and some use cases.
Consider the following when deciding to use snapshots to protect data on virtual volumes.
- Carefully consider what data requires this type of protection and plan accordingly. Do not enable snapshots for all volumes due to the limitations of how many snapshots the storage system can support. When the limits are reached, no snapshots can be created until existing snapshots are deleted. See Dell PowerVault ME5 Series Storage System Support Matrix for the system limits.
- If replication is enabled between two ME5 Series storage systems, the replication process creates internal snapshots which are not visible to the administrator. These snapshots do not count against the per-volume limit but do count toward the system limit.
- Snapshots can be created manually, or created by a pre-defined schedule on a per-volume basis.
- It is not possible to define a common snapshot schedule across multiple volumes. Therefore, if a consistent snapshot is required for a group of volumes, manual coordination must be done from applications and by using scripting and the ME5 CLI API to synchronize and automate the multi-step process. The CLI API is embedded in the controller modules. There is no additional software to install. See Dell PowerVault ME5 Series Storage System CLI Reference Guide for a complete description of the CLI commands.
- Snapshots are treated like any other volumes. They can be attached to hosts and made read-only or read-write.
- Taking snapshots is fast and efficient. They consume no space initially until data is changed in the snapshots.
- Snapshots are logical copies of the source volumes. They depend on the source volumes, and I/Os to the snapshots might affect I/Os to the source volumes. Limit access to the number of copies of snapshots created from the same source volume and monitor performance carefully over time to determine the impact to the environment.
See Dell PowerVault ME5 Series Administrator's Guide on Dell.com/support for a detailed description of the features and how to set up data protection.