In my last post, I talked about the background behind the development of the new DXi6700 dedupe appliances, the DXi6701 and 6702. Now I’ll focus on one aspect of this new product: hybrid deduplication made possible with DXi Accent software.

First a little background. Virtually all dedupe appliances work as target devices in an architecturally similar way. That is, all the data in a given dataset is sent to the appliance, and the redundant elements are discovered and filtered out at the target (different systems use different dedupe methods, but the action happens at the target). This approach is very effective; purpose-built dedupe hardware means uniform high performance and makes it easier to leverage the compute-intensive dedupe that gives the best reduction. But—it means that all the data has to move to the appliance. In most cases that’s OK, but when the network itself is the bottleneck, it can slow down backups, or require heftier network connections.

What if we could deduplicate before data it is sent to the appliance? That’s what several backup software apps try to do, but the problem is that all the deduplication (including index management, space reclamation, data integrity checking, replication, etc.) moves to the backup servers and to dedicated pools of storage. As research shows, setting up that kind of system is complex, expensive, hard to maintain and usually gives poor reduction results.

Enter DXi Accent and hybrid mode dedupe. This new approach moves part of the dedupe process to the user’s media server—the upstream part that identifies the redundant blocks—but it leaves most of the heavy lifting on the appliance. So only the unique blocks in a data set are moved over the network, while the load on the server remains relatively low. Using DXi Accent, a typical backup sends 90-95% less data over the network. So if the network is the bottleneck, the backup could be 10 to 20 times faster (or a lower bandwidth network could be used).

DXi Accent uses the same basic transport as the DXi replication, and it was designed to work over a WAN as well as a LAN. This means that, in some cases, a remote server can be protected by installing a local software plugin instead of a separate target device—with huge potential cost savings. DXi Accent is also flexible; users can enable or disable it on different servers pointing at the same DXi appliance. And it supports integrated features for DR (replication) and long-term retention (direct tape creation), as well. Plus, like other software licenses associated with the DXi6700, DXi Accent is included in the appliance’s base price so it’s extremely affordable.

DXi Accent is currently available on DXi6700 models, supporting NetBackup using OST, and for Linux clients. Expansion to other appliances, backup software and clients will come soon. As always, I welcome your comments, questions and suggestions on DXi Accent and other Quantum offerings.