Feature Spotlight: Global Undelete

Global Undelete is an exciting new feature introduced with Hammerspace 4.2. You can read more about all the new features that we introduce in the Hammerspace 4.2 release announcement.

The cost of data loss is substantial. Human error accounts for a major portion of all data loss events. As our reliance on timely and accurate information increases, we are exposed to new risks. The loss of important files or directories generally results in one of two outcomes: either the data is recoverable with the assistance of technical support or it is permanently lost.

Even in the best-case outcome, when deleted files are recovered, there is typically substantial cost and time involved. Imagine if you could easily restore files through a self-serve function. Desktop and laptop computers already have this function through the “Recycle Bin”. What if there were a global recycle bin across all data resources regardless of the location of data?

This is exactly why Hammerspace is introducing Global Undelete. The Undelete feature empowers end-users to be more productive by extending the ability to recover from data loss. Consequently, Undelete enhances productivity as well as reduces the time and cost of recovering data.

Use Cases and Benefits

Hammerspace Undelete provides a number of valuable benefits to organizations and individuals. These benefits include:

  • Self-service data recovery. Empowers end-users to restore their own files with speed and ease.
  • Eliminates the chance of data loss due to accidental or malicious deletion of files and folders.
  • Reduces the cost, infrastructure, and management required to protect data.
  • Allows backup to focus on protecting the organization and snapshots on end-user productivity.
  • Centralizes data protection across entire organization.

These benefits lead to improved cost savings and faster time to solution. By vastly simplifying data recovery, Hammerspace allows end-users to focus on productivity instead of complex data loss problem solving.

Undelete Explained in Detail

Hammerspace Undelete objective is declarative policy which makes configuration simple and straightforward. It is a set- and-forget-it style of implementation. Thus, complex configuration is replaced with a simple declaration of a desired end-state. Declarative policy objectives, such as Undelete, allows alignment with business process objectives. This is an approach that significantly speeds up operations and saves time.

Granular Control

Hammerspace Undelete offers fine-grained control. Hammerspace objectives, such as Undelete, can be set anywhere in a filesystem hierarchy, from a single file, to anywhere in the directory structure, to an entire file share. An Undelete objective set on a directory will automatically be inherited down the tree, per illustration below.

Regular Expressions and extension pattern-matching can also be leveraged for even greater control over what you want to include or exclude from protection. Thus, you can protect what is valuable to you and your organization while simultaneously avoid protecting the unnecessary, such as temp files. You have full control in your hands!

Hammerspace Objectives support custom metadata tagging. An Undelete Objective can thus include user-defined tags and keywords for additional granular control and customization. There are multiple options for how to leverage this highly useful functionality. Some examples are the Hammerspace CLI, REST API, or the HSTK. You can learn more about the HSTK or Hammerspace Tool Kit here. Along with the toolkit itself, you will also find a rich set of usage examples.


Undelete protection can cover the length of an hour, a day, a week, or an entire month. This covers virtually any need for additional protection of files that have been deleted, either by accident or malicious intent.

Setting retention is as simple as applying the Undelete Objective itself. You simply choose the desired retention time by checking the appropriate checkbox, and then click the “Save” button below. Your files are now protected from deletion during the time you set. It’s as simple as a couple of mouse-clicks. There are, of course, also options for the more command-line oriented. Here is a simple example of what setting an Undelete Objective from the CLI would look like:

First, let’s change the working directory to a mounted share:

$ cd /Volumes/foobar/demo/

Next, I will pick and file and configure an Undelete Objective:

$ hs objective add -e “TRUE” undelete-1-hour IOAnalyzerGuide_1.6_20140326.pdf

Finally, let’s validate that it worked as intended:

$ hs objective list IOAnalyzerGuide_1.6_20140326.pdf

The command results in the following output (snippet) which validates that the Objective has been applied:



|OBJECTIVE = SLO(‘undelete-1-hour’),



Logging into the Admin GUI also validates that the Objective has been applied as intended.

Global and Local Data Protection

Hammerspace Undelete is a global feature. By placing Hammerspace in more than one location, the files protected by an Undelete objective on one site automatically replicate to other sites. For example, files protected by an Undelete Objective in Site A will replicate over to Site B. These files can then be recovered at either Site. Files can thus be protected globally across your entire Hammerspace deployment.

Files protected by Hammerspace Undelete can be easily identified by a unique text string that is appended to the filename. This not only identifies the file as protected by an Undelete Objective, but also protects from an undesirable and unintended create/delete loop. Let’s take a closer look at this would look like. In the following example, we have chosen to protect the file “PDArch.pptx”. A text string has been appended to the end of the filename as you can see below. Once the file has been restored, the renaming persists to ensure loops are not introduced. Furthermore, it clearly identifies the file as having been restored from an Undelete policy.

Administrators are also able to view this valuable functionality from the Hammerspace Admin GUI, as shown in the image below.


Hammerspace Undelete provides self-service functionality. Protected files and folders that have been deleted, accidentally or maliciously, can simply be restored from the ~/.snapshot/current directory. Each individual directory in a protected hierarchy contains its own .snapshot/current subdirectory. As previously illustrated, Hammerspace Undelete protects you from losing valuable data.

Cost Savings

By leveraging snapshots as the underlying mechanism, Hammerspace Undelete provides important savings of valuable storage costs. Hammerspace provides the option of local as well as global snapshots. You can read more about this in future blog posts (coming soon!) or Hammerspace documentation. What’s important for the purpose of Undelete is that by levering snapshots, files and folders protected by Undelete do not consume extra capacity beyond already scheduled snapshots.

Furthermore, this provides a significant reduction of the time and cost associated with traditional backup and restore. By using Hammerspace Undelete Objectives, Administrators can execute less frequent snapshot and backup schedules to protect unstructured data. Hammerspace Undelete is not intended as a replacement of backup but can significantly augment and enhance your data protection strategy at reduced cost.


Hammerspace Global Undelete, as shown, provides a number of benefits to your business.

  • Granular Control: Hammerspace Undelete Objectives are declarative policies that offer simplified yet fine-grained control. You can leverage an existing Undelete Objective or customize through Regular Expressions and pattern-matching. Applying an Undelete Objective can be as simple as a few mouse-clicks to as complex and granular as you choose.
  • Global Protection: Objectives can be implemented on entire shares or exports down to individual files. When an Objective is applied to a share or folder, the policy is inherited down the directory structure.
  • Retention: You control the duration of Undelete protection. Shares, directories, and files can be protected from an hour to a month.
  • Self-Service: This mirrors the Cloud model of self-service. Data that has been deleted, accidentally or maliciously, can be completely protected from loss and easily restored.
  • Cost Savings: Hammerspace Undelete is a feature built on existing snapshots. By extending snapshot functionality to Undelete, Hammerspace Undelete does not consume additional storage space. Hammerspace lets you have your cake and eat it, too!



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