DiskXtender

EMC DiskXtender (also known as DX) is an automated, policy-based, file system-centric solution for migrating inactive data off higher-cost storage to lower-cost disk, tape, or optical devices (hierarchical storage management).

DiskXtender is produced by EMC Corporation and is supported on Windows, Linux, and Unix environments. As of August 2011 DXUL-SM (DiskXtender Unix/Linux Storage Manager) will see this product become end-of-life.

The Windows version of DX implements a file-system filter driver that intercepts user mode I/O requests. These intercepted requests are then processed by DX components. If necessary, files are fetched off of secondary storage media and then passed back to the calling applications. Otherwise, if no processing is necessary, the filter driver does nothing and simply passes the request through the stack of lower level drivers. Other applications that implement similar architecture in terms of file system filters include anti-virus and file system replication software.

Information Lifecycle Management As of 2003, DiskXtender is one of the three ILM offerings from EMC after EMC acquired Legato and focusing on File System archiving. The remaining two products include EmailXtender and DatabaseXtender which archive emails and database correspondingly.

In any environment, a majority of data can be categorized as inactive (either not modified nor accessed for a long period of time) but yet still stored on primary storage. This results in a multifolded growth in capacity for production storage which increase costs for storage, protection, disaster recovery and management. For example, a file system of 1TB with annual growth of 25%. Every year, 25% data will need to be stored, protect, DR etc. which means 25% growth in all the storage, protection and DR systems. If, supposed 60% of the data is inactive and can be moved safely off the production, with the same growth rate, changes to the production system is only 40% * 25% =10% which is much easier to cope with.

DiskXtender, by intercepting I/O from operating system, is capable of detecting inactive data and then migrating those data to secondary and/or tertiary storage with lower cost/GBs while still maintaining transparency to both applications and end users. Applications and end users have full visibility of migrated data and when access is requested, those migrated data will either be redirected to users and applications or copied back to the production system.