Equallogic: Snapshots are not Backups

By admin, June 30, 2012 08:02

Got this interesting fact from the latest EqualLogic Customer Connection (June 2012).

So at the end you still need a proper backup solution from vendors like Veeam, PHD, Symantec or Acronis.

Question of the Month

Snapshots are not Backups

Q: Are Snapshots a replacement for backups?

A: Snapshots are point in time copies, stored with the original volume in a SAN. Snapshots provide improvements to backup operations in open file handling, and the ability to offload the backup copy operation to a different server than where the application is running.

While snapshots provide a fast and efficient way to create copies of SAN volumes, the snapshots are still stored with the SAN volumes. This means that both primary application data and its snapshots are vulnerable to catastrophic loss scenarios such as fire, flood and earthquake. Any administrative mistakes can not only open the possibility to loss of primary data, but also the snapshots of this data.

Snapshots are also inherently temporary – while an administrator can ask the system to keep many snapshots, they typically have a life span measured in weeks to months, rather than years as typical of backup archives. Depending on your system policy, they also may be deleted automatically to make room for newer snapshots.

Well-designed true backup environments ensure that copies of data are regularly created and stored separately from the primary volume data. Typically this backup data is stored in a secure location away from your primary storage devices, and retained for months to years depending on your organization’s policies. In this configuration, the backup data can be used both for small data recovery operations, such as user accidentally deleting a file, as well as to recover from a catastrophic failure such as a fire or flood in the data center.

Dell EqualLogic strongly recommends customers design and run a comprehensive back up environment, and consider utilizing snapshots as part of this environment to improve backup operations.

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