Virtualization appliances do present a single, ubiquitous storage interface to servers on the front end and simplify the presentation of the different types and tiers of storage on the back end while allowing migration of data between the different tiers, but a clear understanding of the correct hardware for each unique infrastructure is still lacking.
This considerable gap between the promise and reality of a manageable tiered storage architecture means that users are often left to fend for themselves when deploying high-performance monolithic arrays alongside lower-cost midrange arrays that include a myriad of RAID configurations without a cohesive way to move data between the different arrays.
Part of the problem is that the lower costs of second and third tiers of storage lure users into buying the wrong tier of storage. Hitachi Data System's chief technology officer, Claus Mikkelson, finds that users who neither plan their storage strategy nor try to understand application requirements before procuring storage end up with a configuration that does not meet the application's needs. "As a result," Mikkelson says, "users end up in a trap from a performance and reliability perspective."
Another problem is that IT managers are often left alone to drive all the changes necessary to deliver on the benefits of a tiered storage infrastructure.
MidAmerica Bank IT manager Paul Stonchus manages an all-EMC environment that is made up of about 5 percent DMX, 65 percent Clariion and 35 percent Centera arrays as well as tape storage. But the Naperville, Ill., bank's mainframe computer output to laser disk (COLD) application is the only one that takes advantage of tiered storage.
Stonchus plans to extend tiered storage benefits to his e-mail archive application by the end of the year. But he also needs his systems and business analysts to understand tiered storage technologies so they can better utilize tiered storage for their applications. "I can't make ILM [information life-cycle management] a reality all by myself," Stonchus says.
Yet another problem that users encounter is the architecture and maturity of products that manage the movement of data between tiers of storage. Ruth Mitchell, a storage administrator at a university in upstate New York, used to move files between different tiers of back-end storage using the Hierarchical Storage Management feature in IBM's Tivoli Storage Manager for what had been an all-AIX environment. When the university switched to Windows a few years ago, IBM did not have native Windows support, and Mitchell could not find a third-party product mature enough for her shop.
To deal with the hurdles mentioned above, new classification and virtualization products are emerging that allow users to get the full benefits of tiered storage deployments. Scentric Inc., in Alpharetta, Ga., sells a product called Destiny that allows users to discover, classify and move data on Windows servers and CIFS-compliant network-attached storage (NAS) appliances without the use of agents.
George Rodriguez, an IT manager at ABC Distributing LLC in North Miami, Fla., recently introduced tiered storage into his shop after using Scentric's Destiny data classification tool to help the savings from ILM materialize.
Prior to using Destiny, Rodriguez was constantly allocating more Tier 1 storage on his high-end IBM Shark array to deal with the data growth on his Windows servers. "I had the IBM Shark divided between mainframe and Windows but had to occasionally empty IBM Shark LCUs [logical control units] assigned to the mainframe so I could re-assign them to my Windows servers," Rodriguez says.
Using reports produced by Scentric's Destiny, Rodriquez was first able to show management and users how many old files they were storing and how infrequently those files were being accessed. Rodriguez now sets policies that automate the classification, movement and retention of files on his Windows servers.
Scentric's reporting feature allowed Rodriguez to justify to his managers the purchase and introduction of another tier of storage at half the price of Tier 1 storage without increasing management overhead and costs. Rodriguez configures Destiny to keep files on Tier 1 storage for 45 days, on Tier 2 for another three months and then moves the files to another location where they are backed up and then deleted from disk. Rodriguez's says his only regret so far is, "I wish Scentric offered similar functionality for the mainframe."
Organizations are also deploying array-based block virtualization to better manage and control their tiered storage environments. Fidelity National Title Group Inc. in Jacksonville, Fla., covers nearly one-third of all U.S. real estate title insurance policies and needed a system that would handle the 2.5 million transactions it processed annually. The system also had to maintain its online repository of 45 million historical documents.
To manage the data, the insurance company implemented a three tier storage design that uses Hitachi's TagmaStore Universal Storage Platform (USP) for Tier 1 high-performance storage requirements, which in turn virtualizes the company's Tier 2 HDS Thunder 9585V modular storage systems. This architecture enables non-disruptive migration of their data between tiers and access to data with lower-performance demands when application needs dictate.
Another product that allows users to more easily manage tiered storage deployments is Bycast Inc.'s StorageGRID product. Vancouver, British Columbia-based Bycast sells its technology as a CAS (Content Addressable Storage) appliance that is accessed by servers over Ethernet connections using standard CIFS and NFS protocols. Though it uses a NAS-like interface, unlike NAS appliances StorageGRID indexes and classifies files as they are stored and gives users the option to virtualize both disk and tape storage. Users may then set policies to manage the placement of data storage devices. The policies control a file's retention period as well as its placement and movement between the different back end tiers of storage.
The StorageGrid product also allows users to introduce single instance storage (SIS) into their environment. SIS has the potential to reduce the total amount of storage an organization needs by eliminating multiple copies of the same file from being stored on network drives. The technology scans each file creating a unique identifier for it and then only stores the file.
Yet with any of the above approaches to managing tiered storage deployments, users still need to look before they leap. For example, Scentric's Destiny offers users the ability to scan and index the content of files before they are stored to expedite future data discovery. But if users set too many indexing parameters, performance and storage requirements increase as files take longer to scan and indexes consume more storage capacity to accommodate the additional search criteria.
Bycast's StorageGRID SIS feature reduces back-end storage consumption but may not provide the rapid access to data that certain servers or applications may require. Also, organizations that only store unique files such as X-rays or check images will not experience these storage savings as each X-Ray and check image is unique so duplicate files are never created. And HDS's TagmaStore USP platform still lacks any native abilities to either classify data or manage portable media like tape or optical on the backend.
New data classification and virtualization software and CAS appliances are helping users in all size shops start to bridge the gap between the promises and reality of tiered storage deployments. But other companies are still waiting on vendors such as CA Inc., EMC and Symantec Corp. to integrate their software acquisitions of the last few years and deliver products that deliver enterprisewide data classification and migration capabilities.