Information Faster Blog

XAM - Why do we need yet another storage standard??

By David Martin

I just returned from Storage Networking Word (SNW) in Dallas last week where there was a lot of discussion and excitement about the Extensible Access Method (XAM) specification.  These were not the typical ‘inside the box’ vendor centric discussions. Rather, XAM early adopters and end user visionaries were enlightening us in the vendor community with new and fresh insight into where XAM fits within the bigger picture.  These discussions got to the heart and soul of why the XAM standard is so critical to the storage industry.

At the most basic level, XAM is a search-enabled standardized storage device interface for e-discovery, governance and regulatory compliance applications which provides interoperability across storage devices, lowers ISV porting/testing costs and extends information accessibility through search.   But XAM is actually more than just a standard.  It also addresses at least two other key industry problems: information authenticity and multiple classes of storage.

XAM enables information authenticity.  No other industry standard storage-related API or protocol (i.e. file system APIs, CIFS/NFS, etc)  sufficiently addresses the authenticity issue.  Authenticity is defined as: a property of information, including its content (the data) and metadata, that identifies that it is currently what it was originally and verifies that it has not changed over time. (Source: DMF, NARA, Society of American Archivists).  Without authenticity, information is useless for regulatory compliance, e-Discovery, and corporate governance purposes.  Key authenticity features of the XAM specification are that XAM atomically embeds metadata with content in the XAM object structure, and the metadata fields in the XAM object can be designated ‘static,’ effectively addressing the authenticity criteria in the definition above.  

The other market-changing capability that XAM enables is classes of storage.  XAM has been promoted primarily as an interface to compliance-enabled storage devices (i.e. non-tamperable, searchable, retention managed, fixed content).  However, several of our customers want to extend the XAM interface to other SAN and NAS primary storage tiers as well as low-cost storage such as SATA and FATA arrays, while still maintaining basic XAM interoperability, retention management and search attributes. 

An example of this type of customer is Pennsylvania State University.  Penn State has petabytes of web-accessible  digital content across their departments.  These collections contain graduate student thesis, research data, historical pictures of Pennsylvania, and a multitude of other discipline specific-content.  Penn State departments package, classify and organize their data, then turn it over to Penn State IT to manage. 

This approach obviously introduces challenges for Penn State IT, including extending search across all digital collections (department libraries are silo'ed and only one can be searched at a time), reducing storage costs (by placing data on multiple storage tiers), and scaling all this to hundreds of millions of objects.  And if that isn't enough, the National Science Foundation (NSF) and the National Institute of Health (NIH), the source of the bulk of research funding, now mandates that all research projects be electronically stored and discoverable.

What customers like Penn State want to be able do is to be able to distribute their XAM objects across these different classes of XAM-enabled storage devices based on quality of service policies, search across all these classes of storage with a single search, and even be able to migrate these objects to other XAM classes as the QoS requirements change.  All of these storage classes must be accessible through the same XAM interface and must still maintain standard XAM search and retention management capabilities.  Extending XAM to SAN/NAS storage has been designed into the XAM v1.0 specification, so this is not a technical problem, but defining the conformance criteria of XAM base services on primary and secondary storage tiers will need to be defined by the SNIA XAM Initiative and XAM community.

XAM is uniquely suited to address these industry needs.  Regardless of whether customers have legal, governance or regulatory compliance needs, or have broader e-discovery and cost-efficiency requirements, they should demand XAM support from their application and storage device vendors.

For more information on XAM please visit the SNIA XAM webste at  Please monitor this blog site for future XAM discussions.  I work in the HP Information Management business unit and am co-chair of the XAM Initiative inside SNIA.

| ‎11-05-2009 12:20 PM

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| ‎11-05-2009 12:25 PM

Nice update, I am willing to be regular reader of  your blogs.

I belong to <a href="">hdd data recovery Solution In India </a>, so I have big interest in Computer related updates, we deal to recover lost data from computer hard disk and all other storage medias.

| ‎11-09-2009 09:53 AM

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| ‎11-16-2009 09:23 AM

This is true that XAM enables information authenticity.

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