Storage area networks (SANs) may have started out as largely Unix creatures, but no longer. With the price of SANs coming down, more and more Windows servers at a growing number of companies are attaching to SANs. Network-attached storage (NAS) is also a popular approach to accommodating data growth for Windows applications.
For storage managers, increased reliance on networked storage for Windows brings with it new management challenges. Windows behaves differently than Unix and requires dissimilar processes and procedures for some tasks, such as bare metal restore. Heterogeneous shops must decide how to manage the two environments as islands or in a unified manner.
Even Windows-only shops must decide whether they want to use that platform for management functions that require high security or stability, such as virtualization. Despite all these issues, though, networked storage is gaining momentum for Windows shops. Case in point: QuadGraphics, Pewaukee, WI, prepress and printing specialist with more than 10,000 employees in 18 sites nationwide, which recently began upgrading its server and storage environment from Windows NT to Windows 2000.
With around 500 Intel-based servers and a SAN offering more than 25TB of managed storage, the migration is a major effort that's still progressing. Improved storage with Windows 2000 management features has made the upgrade more than worthwhile. For example, 24x7 storage availability is so fundamental to QuadGraphics' business,
He says, "When we had NT and needed to grow our storage to match our business, it was at the expense of production. The strides from NT to 2000 were extraordinary: utilization, performance and the ability to manage storage are vastly improved, and we can add storage sets without having to reboot. All of this allows for uptime to the user and lets us upgrade storage transparently."
QuadGraphics' positive experiences with Windows confirmed that the environment represents the way forward. Unix servers—once relied upon for what was once seen as their superior storage management—now support just a few high-availability databases. Future growth will largely deepen the company's investment in Windows-managed storage.
The path of least resistance
Storage managers with high-volume storage requirements are often already comfortable with Unix, and may be loathe to complicate things by introducing Windows servers offering little benefits when it comes to storage management. That's been the case for application service provider, Appshop, of Fremont, CA, where Unix storage predominates and Windows is only used where necessary.
Appshop offers customers a range of hosted Oracle applications using more than 250 Sun Microsystems Solaris 2.8 and HP-UX 11i Unix-based application and Web servers, 30 Windows-based servers and an array of Network Appliance F840 NAS devices providing 45TB of storage between data centers in Santa Clara, CA and Denver, CO.
Approximately 98% of storage is formatted using NFS3 to support the Unix servers, according to Mike Jennings, senior vice president of technology with Appshop, who says Windows is only used where a particular Oracle application hasn't been ported to Unix. Because the company's storage strategy has been to offload capacity onto the NAS boxes, Appshop has been able to ensure quick recovery of servers by simply changing the IP address of hot-standby Unix systems, then remounting the volumes onto the servers.
Because Windows installations create unique configurations within the Windows Registry, failure recovery takes longer within Windows environments. Since uptime is key for Appshop, such delays negate any advantages Windows might provide. Backups are also easier, since production data largely comes off of the homogeneously configured volume.
"Supporting Windows is a challenge compared to Unix," says Jennings. "When you get to the NT environment, everything is heterogeneous; each OS has a different configuration within the registries. We've chosen the [Unix and NAS] direction to keep things simple. Because of the disk environment we run, it's been very straightforward."
Steep learning curve
Despite Microsoft's efforts to give Windows feature parity with Unix, differences still persist.
Robert Dominique, senior Unix system administrator with the Canadian Space Agency (CSA), in Saint-Hubert, Quebec, knows all too well the differences between Windows 2000 and Unix-based storage management. The CSA maintains two separate SANs, with 1TB of storage supporting high-end Unix computing applications and a second, 3TB Dell-based SAN supporting Windows administrative software and file-and-print services.
As CSA's workforce has grown to around 800 employees, managing Windows partition has grown commensurately while the Unix environment has maintained relatively static. That presented a steep learning curve for Dominique's team.
"The Windows and Unix SANs were not in the same league," Dominique says. "The Unix technology is much more of a higher level [solution] where the management is done on the SAN, but the Windows one was really at the lower end: You put the management software on each client, so it's decentralized and offers more risk for error."
While it's easier to manage business continuity and backup strategies across fewer platforms, homogeneity is a luxury that's disappearing. Storage managers are—or will soon be—dealing with a heterogeneous array of operating environments with storage to match.
Effective storage management requires choosing a management platform capable of bridging the gaps between environments and, in particular, delivering Unix's robust enterprise-class data management features to still less-mature Windows environment.
QuadGraphics' Thomas, for one, points to Windows' "very limited toolset" for repairing file system damage on the fly—without compromising users' access to their data.
"Windows offers a lot of flexibility that we can pass to our users," he says. We can fine-tune how we present that storage to our end users. But having to basically bring the system down to perform a chkdsk [imposes] an expensive time cost on our production."
Java consoles gaining favor
Even with Windows Server 2003 adding new storage-related features, it will take time and experimentation to ascertain how they measure up with their Unix analogues, and still longer before its storage services are mature enough for many storage administrators to bet their jobs on. This could also dampen demand for the many new NAS devices playing the ease of manageability card by incorporating a Windows .NET kernel.
The problem is compounded by the differences in complexity and maturity of enterprise management platforms themselves. Whereas most SAN vendors provide proprietary management tools, operating system limitations mean that comparable versions of the tools don't always offer exactly the same features.
Recognizing that each platform will have its supporters—and its role within the enterprise—many storage ISVs are bridging the gap with Java-based management consoles that deliver a common management standard to both worlds.
"Early adopters of SAN technology are looking for ways to better utilize those SANs," says Karen Dutch, vice president of marketing with management software vendor InterSAN, of Scotts Valley, CA. The company's Pathline storage management tool runs across Windows NT, 2000 and Unix servers. "They have NT SANs, Unix SANs and all these islands that didn't provide much more benefits than DAS [direct-attached storage]. Customers are looking for consistency and want a level of abstraction that goes above any one tool."
Pathline, like many products in the emerging storage resource management (SRM) market, provides that abstraction by automating common storage management tasks—the system ensures compatibility with a range of SAN hardware, regardless of operating systems.
In such an environment, storage is measured in terms of availability, asset management, security configuration and monitoring and storage provisioning. And because it's based on Java, the management console can be run from anywhere on the network. In many cases, the complexity of managing large numbers of distributed servers and storage devices works against the storage manager no matter which operating systems are installed. IT staff at the City of Winnipeg, Manitoba, found Windows was more than adequate once they centralized the backup and recovery of data across the city's many departments and applications, then used IBM Tivoli Storage Manager (TSM) to provide consistent data recovery across a raft of Windows NT and 2000, Novell NetWare and Sun Solaris-based servers.
Historically, storage within the various departments—running major applications including PeopleSoft, the Oracle database, Microsoft Exchange and DB2 Data Warehouse as well as Web hosting and file and print services—had been managed separately from more than 15 different locations. This led to a large amount of DAS storage split over a hundred servers, which presented a storage management headache.
Highly distributed storage also made it difficult for individual departments to cost-justify the expense of a high-end tape library. By consolidating their storage backup and recovery onto an IBM 3583 Ultrium Scalable Tape Library, the departments improved management, backup, recoverability and systems availability. The city soon expects to upgrade to an even larger IBM 3584 UltraScalable Tape Library.
Winnipeg's IT team have found Windows to be more than adequate for management of typical backup and recovery services. "Most other companies implement TSM on Unix, but one of the major reasons we went with the Windows solution was because the cost of the server was much lower," says Terence Chan, systems software administrator with the City of Winnipeg. Using Windows also provides a more seamless interface for the city's employees, who are running Windows desktops and can log directly onto the TSM console to browse and recover backed up files. Such democratic storage management would be unthinkable in a Unix-based environment designed mainly to move data from server to tape as quickly as possible.
Clearly, there are still a range of opinions as to which is the better platform for storage management. Unix has its robustness, maturity and broad feature set behind it, while Windows benefits from a short innovation cycle, lower price and the easy integration with desktop platforms and other servers.
Homogeneous environments are naturally easier to manage than those with multiple platforms, yet the way application environments are going it's clear that homogeneity will become increasingly rare—unless it's due to standardization on Windows at Unix's expense. In the meantime, businesses running both environments need to carefully assess various vendor approaches to ensure consistent storage management that reaches from one side of the enterprise to the other.
About the author: David Braue is a frequent contributor to Storage magazine. He last wrote about mainframe storage.
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