According to the latest research conducted by the Enterprise Strategy Group (ESG), over 50% of all corporate data...
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is "fixed content" and includes documents, images and e-mail. What's more, this data is growing at 90% per year, ESG estimates.
Such enormous growth puts huge pressure on storage resources, which is why storage administrators are turning to content-addressed storage (CAS) technology to relieve the burden. However, this technology is new and initial implementations have been tough going, users report.
Fixed content refers to files that don't change, are accessed infrequently, but must be readily available when needed and are retained for prolonged periods of time.
Saving time and space
"We needed the ability to restore information in seconds," said Jason Hardy, network analyst at RadioFrame Networks Inc. "The ability to actually roll back to older versions of the information was key," without long and arduous tape examinations, he said.
After evaluating a variety of tape systems and CAS products, the company bought the Axion system from Avamar Technologies Inc. for its speed and data reduction capabilities -- more than 1.5 terabytes (TB) of data is now being backed up to only about 800 GB of space.
Hardy appreciates the fast backup/restoration and version control capabilities brought by the Axion, though he notes that data management tasks can be a bit cumbersome. "It's very bulky," he said. "It has to hop in and out to several different applications to get the information you're looking for." It's a problem that seems to permeate the industry. "I don't think that the vendors out there have done a very good job of bringing it all together into one application." Hardy is expecting better management tools for the Axion to appear sometime in 2006.
Hardy is also hoping for more speed (especially across remote links) noting that current replication speeds are limited to 10 gigabytes per hour -- primarily due to file system limitations. "It's just taking a very long time to replicate all of that information we have because of the file system bottleneck at that level," he said.
In addition, Hardy feels that CAS support for Exchange needs some improvement. "It's a little bulky when you're trying to do message-level backups because it actually opens up every e-mail and every mailbox and your Exchange system takes a hit on that [during backup]," he said, though improvements are expected in Avamar's version 3.5 software release.
Meeting regulatory requirements
In the banking world, check handling has demanded significant attention. In the past, check images were relegated to microfiche and stored in a vault. Later on, the images were recorded to DVD. But recalling check images proved to be a labor-intensive process. Requests had to be made, the media had to be pulled and the correct image could then be located. Banks realized that check images could be digitized and moved to long-term, readily accessible disk-based archival storage systems, such as EMC Corp's Centera. CAS helps the bank to meet regulatory retention needs and provides a far better level of service.
"We were able to replace the need for DVDs with Centera," said Paul Stonchus, first vice president, data center manager at MidAmerica Bank. "And now for all intents and purposes, the end user is totally unaware that the image they're receiving is a year old, but the response time is less than one half of a second."
Stonchus underscores the spiraling need for archival storage, noting that his utilization of CAS space is escalating at a significant rate. MidAmerica's first Centera was installed in March of 2004, the second system is about six months old, the third system is just two months old and a fourth system was acquired just last month -- totaling about 4 TB of Centera space today. Over the next 12 months, Stonchus expects his CAS capacity to double again. Plans are also underway to establish another Centera platform at a remote location for off-site data replication.
While Stonchus expressed concern over Centera's up-front acquisition costs, he noted that the total cost of ownership has been comparable to tape-based systems. "The number of hours per week spent administrating Centera is maybe one half hour -- tops," he said.
The biggest challenge that Stonchus sees with CAS products is getting vendors to support the storage systems with their software applications. "Talk to application developers and find out if they're prepared to write/read data directly from a Centera [or other CAS] device," he said. "Otherwise you end up having to put in a gateway solution."
Picking the right product
Healthcare facilities deal with high volumes of fixed content, such as patient records, X-ray images and MRI data. Placing this fixed content on a CAS infrastructure offers important cost and service benefits to organizations like Banner Health. "WORM [write once, read many] is exactly what radiology applications are all about," according to Tim McFarlan, systems director, technology management at Banner Health.
The trick for McFarlan was to find a CAS platform that proved suitable for Banner's Picture Archive Communication System (PACS) application used to manage and share digital radiology images across Banner's 21 hospitals in seven Southwestern states.
An early CAS implementation using EMC Centera resulted in connectivity and other IT issues, as well as serious proprietary limitations that impaired interoperability with other PACS vendors.
Today, McFarlan uses Bycast Inc.'s StorageGRID CAS software to handle about 175 TB of PACS data, covering about 10 hospitals. He expects to complete the digital conversion across all of Banner's facilities in the next two years.
Bycast's grid storage approach allows for fault tolerance, allowing copies of data to reside in multiple locations -- hospitals can continue to operate even if Banner's network is interrupted or trouble strikes one storage node, McFarlan said.
Although the move to CAS demanded careful, transparent data migration, McFarlan reports that the technology is performing well and the organization is generally satisfied with the transition thus far. "We did come through a very rocky road," he said. "We've had to ramp up rapidly and we've made some mistakes, but overall I'm really happy that we've settled on this technology." His major hope for the future is to see added flexibility with metadata and archive change management to allow for more convenient data updates (e.g., patient name changes) as the need arises.
Content-addressed storage: An overview
Content-addressed storage: Strengths and weaknesses
Content-addressed storage: The vendors
Content-addressed storage: Future directions