Backup Physical Tape Replication

Perspectives on Symantec OpenStorage

A couple of weeks ago SEPATON demonstrated OpenStorage (OST) at Symantec Vision and I posted a blog entry including a link to the demo. I wanted to explore OST in more detail.

OST is Symantec’s intelligent disk interface. It works with all types of disk targets and is most commonly implemented with deduplication enabled storage. OST addresses disk as disk and is different from the traditional tape-based metaphor. It handles backups as images and allows the backup application to simultaneously read and write data and incrementally deleted expired information. OST enables access to NetBackups native disk features such as San Client Backups, Media Server Load Balancing, Intelligent Disk Capacity Management and Storage Lifecycle policies. These are features of NetBackup that can benefit end users and are outside the scope of this blog. In this post, I want to discuss the features that are unique to OST.

The challenge that end users grapple with is how to move or transform data using their backup appliance while maintaining NetBackup (NBU) catalogue consistency. This can be a particularly difficult when using appliance-based tape copy or replication. OST addresses these issues by enabling the appliance to access the NBU catalogue. This means that NBU can instruct the appliance to replicate a copy of the data and maintain separate retention policies on the two copies. Let’s look at these features in more detail:

Optimized Duplication – Yes, this is really the name and I did not mistakenly exclude the “de” before duplication. This is Symantec’s name for intelligent replication. The technology enables a deduplication appliance to replicate only deduplicated data to a remote site while maintaining catalogue consistency. It simplifies the process of replication and management.

Open Storage Direct-to-Tape – In the past, vendors have promoted the ability to create physical tape copies without the intervention of a media server. This capability was promoted as a way to overcome bandwidth constraints, but it created a management challenge because NBU’s catalogue was not involved in the tape creation process. OST enables the VTL appliance to create physical tapes directly in a catalogue consistent fashion. It also allows for different retention times on the VTL resident and tape resident images.

Optimized Synthetic Full Backups – Synthetic Full Backup has been a feature of NetBackup for years. The technology enables NBU to create a new full backup based on the full backup and subsequent incremental backups. The challenge with the initial implementation is that substantial disk or tape I/O operations were required to create the synthetic full backup. The new feature takes advantage of the pointer based technology used within many deduplication and allows the appliance to synthesize the full in an automated fashion. Like the previous two examples, the synthetic full would be created in a catalogue consistent manner which simplifies its creation and management.

All of these features are unique to OST. However, it is critical to note that just because a vendor supports OST does not mean that it supports all of these features. Each vendor must write their OST plugin and decide which of these features to support. Today, the vast majority of OST implementations support Optimized Duplication while very few support Open Storage Direct-to-Tape or Optimized Synthetic Full Backups. When considering a solution you should discuss your vendor’s implementation and the features they support. If you are wondering about SEPATON, we will support all of these features over time.

Symantec should be recognized for their work on OST. They have created a technology that provides real customer benefits. They also should be acknowledged for the openness of the technology. They have made OST an open standard and encouraged all disk vendors to adopt the technology. This provides customers with the choice to choose the OST enabled solution that best works for their environment.

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