SAN integration challenge

Storage technology marches on

Storage technology marches on. SANs are faster, easier to scale, higher performing, and more robust than ever — individually. However, the challenge of integrating multiple SANs remains vexing. Although integrated reporting and alerting is easy, it's nearly impossible to truly merge multiple vendors' storage networks without using invasive storage virtualization servers that add their own layer of complexity to the network.

That sums up the results of SAN management tests performed by InfoWorld at the Advanced Network Computing Lab at the University of Hawaii in July. Immediately following Test Centre Senior Analyst Mario Apicella's hands-on test of the latest SAN hardware solutions from EMC, Hewlett-Packard, and IBM , the integration portion of the test began. We asked the three hardware vendors to merge all three SANs into a single SAN. We also invited Fujitsu Software Technology (Fujitsu Softek), as a hardware-agnostic storage software provider, to take part in that challenge.

"Challenge" was the operative word in this test, partially due to the complexity of the task of merging heterogeneous SANs and partially due to unexpected difficulties with the test plan. Our goal was for the vendors to offer as much functionality as they could, in terms of unifying both the administration of multiple SANs into one console, and then be able to integrate storage resources between the SANs.

True integration proved impossible for several reasons. One was the newness of some of the test hardware. The vendors hadn't seen some of their competitors' latest arrays yet and didn't have drivers to support the hardware. In other cases, vendors were loath to grant their competitors unrestricted access to their cutting-edge SAN hardware.

Further, our test plan did not stipulate a "known state" that the network would be left in, so that each vendor actually faced a unique integration challenge of unraveling its competitors' products before attempting to implement its own solution. Thus, in acknowledgement of the lack of parity in the test environment, we've chosen to forego scoring this test, substituting instead a checklist of features and functions demonstrated by the vendors.

But the fact remains that SAN technology hasn't evolved to the point where true integration is achievable, even under perfect conditions.

The results: The software-based management tools that EMC and HP provided couldn't take full control of competing SAN hardware, even when those SANs were integrated at the fabric level by tying together the FC (Fibre Channel) switches. They did offer unified administration of multiple SANs, which is helpful, but not the panacea we were seeking.

By contrast, Fujitsu Softek and IBM offered much more complete integration by inserting their virtualization servers into the fabric and by flowing all traffic through them. Although Fujitsu Softek provided the highest levels of integration in our test, even it couldn't provide full access to, and full control of, everything on the combined SAN. Plus, the virtualization solutions added another layer of software hierarchy to the storage network and created a potential performance bottleneck and single point of failure.

EMC and Hewlett-Packard, the two vendors that supplied software-based storage management solutions, weren't able to completely integrate the storage networks. In fact, they couldn't get close: Their offerings were limited to providing unified administration of the different SANs.

That's not to say that those software tools wouldn't be valuable; to the contrary, they're perfectly suited for many day-to-day operations such as resource discovery, status reports, and alerting in case of faults. Both perform admirably, however, EMC has the definite edge in terms of device support, functionality, and toolset integration.

The Virtualised Solutions

The storage integration systems presented by Fujitsu Softek and IBM are ostensibly similar, each with a software console that presented a unified view of the combined network, and a virtualization server that went a step beyond to consolidate all storage assets into a single pool — actually, into a single, large, virtual drive that could be partitioned and allocated to servers as needed. However, the solutions differed in implementation.

IBM's software was focused on compatibility with IBM's storage arrays, and its Volume Controller virtualization server was implemented as a hardware-based appliance. By contrast, Fujitsu Softek's software is designed for heterogeneous environments, and its Storage Provisioner virtualization solution, a software application, can be installed on standard x86 servers.

Based on the tests, we believe that Fujitsu Softek has the most robust storage-networking interoperability solution and a more intuitive user interface. IBM ran a close second; IBM's Volume Controller virtualization appliance was only released a few weeks before the test, and we expect it will swiftly evolve into a stronger offering.

Fujitsu Softek

Fujitsu Softek started with a disadvantage going into these tests. As the fourth and final vendor, following the hardware manufacturers, the entire storage network was in considerable disarray. Nevertheless, the company's SANView 5.1 storage management software was able to perform discovery, analysis, administration, and reporting across the entire storage network with ease. But despite assistance from Apicella, who had administrative access to the EMC, HP, and IBM systems, the Fujitsu Softek engineers had difficulty taking full control of some storage systems on the combined FC fabric, particularly the IBM gear.

Still, that didn't stop the plucky Fujitsu Softek team. Concerned about exactly this potential situation, they shipped their own low-end disk array to the test lab, installed it onto EMC's switch, and demonstrated their storage virtualization solution on it as well as on the EMC and HP portions of the test network. This was enough to demonstrate not only that their system works, but that both the SANView software and Storage Provisioner 2.1 virtualizing server are more cross-platform friendly than the other solutions used in this test.

I was impressed by Storage Provisioner's flexibility. It can be deployed onto x86 servers of any size; installed in very redundant arrangements consisting of two, three, or more servers; and configured to have a varying number of FC host bus adapters configured either to virtualize servers or storage. Considering that some networks may have more servers than storage arrays — and others may have more storage than servers — the solution's extreme configurability is noteworthy.

The user interface for Storage Provisioner server is excellent. So, too, is the interface for SANView storage management software, which acts as the master control console for the integrated SAN. Even without virtualization, SANView goes far in unifying the administration of the three storage networks, based on a server-based repository of data that it gathers about the configuration of the entire network, called Storage Manager Server.

Unlike the other offerings, it doesn't play favorites; there's no built-in bias toward a specific set of hardware products and no requirement for specialized agents. SANView offers strong, role-based security levels, offering a solution that's much more configurable than the IBM and HP offerings and on par with EMC's sophisticated access-control mechanisms.

That's not to say that there's no room for improvement. SANView's programmers could learn from EMC's designers, who added wizards to help with frequent tasks and policy-based tools for automating administration into their ControlCenter tool. Still, its capabilities for zoning arrays and managing FC switches was impressive, as were those for setting up and executing complex, multistep tasks such as simultaneously changing multiple zonings.

For a green-field installation where there's no pre-existing favourite storage management solution, or where there's a genuine need for the integration of multiple SANs, the Fujitsu Softek solution was at the head of the class — and even in an EMC, HP, or IBM environment, it would be worth close scrutiny.

IBM

Big Blue's entry in the SAN integration bake-off consisted of two management applications from its Tivoli brand, Storage Resource Manager and Storage Manager, as well as the newly released Tivoli TotalStorage SAN Volume Controller virtualization appliance.

The idea behind that mouthful is a pair of 1U-high servers, each built on an IBM's eServer xSeries 335 dual-processor Xeon server running Linux. Each server sports custom software from IBM, as well as four HBAs (host bus adapters). Those HBAs are connected to the FC fabric in pairs, two for controlling storage arrays and two for virtualizing the storage to servers. IBM only sells the Volume Controller in pairs to offer fail-over.

Because it's an appliance, setup and administration of Volume Controller is very easy — even easier, in fact, than Fujitsu Softek's Storage Provisioner. Both systems are designed to discover and "capture" unused storage resources, and then make them available to other servers as though they were a single storage array. Both can migrate existing storage arrays — even if they've been assigned to servers — over to the virtualised model, where they can be expanded, condensed, mirrored, snapshot, flash copied, backed up, and migrated between different hardware arrays without affecting the servers or applications.

The big challenge for Volume Controller is that although any server connected to the SAN — Windows or Linux on x86 servers, or Solaris on Sparc — could access the virtualised storage, disk arrays were another matter. The only officially supported devices for it are IBM's own storage arrays. (The IBM team was able to take partial control over some of the EMC hardware, but the team members stressed that this was an unsupported configuration.) So, despite Volume Controller's appeal, it falls short on interoperability.

IBM's two software-based storage management tools were also Big Blue-centric, with limited capability for managing noncompany hardware. SAN Manager administers the storage arrays on the FC fabric; Storage Resource Manager provides the tools for allocating nonvirtualized storage resources to particular servers. If the Volume Controller is installed, Storage Resource Manager integrates tightly with it and greatly automates the task of assigning storage.

For a datacentre seeking to integrate multiple IBM-based SANs, the Tivoli solution is the right answer, but it's not a general integration solution for heterogeneous networks. If future versions of Volume Controller can expand beyond its Big Blue-centric approach, it could evolve to be a formidable competitor to Fujitsu Softek.

The Nonvirtualised Solutions

EMC and Hewlett-Packard, the two vendors that supplied software-based storage management solutions, weren't able to completely integrate the storage networks. In fact, they couldn't get close: Their offerings were limited to providing unified administration of the different SANs.

That's not to say that those software tools wouldn't be valuable; to the contrary, they're perfectly suited for many day-to-day operations such as resource discovery, status reports, and alerting in case of faults. Both perform admirably, but EMC has the definite edge in terms of device support, functionality, and toolset integration.

EMC

As with HP and IBM, EMC's storage management software, ControlCenter, is focused on its own hardware solutions, especially its disk arrays, such as the Clariion systems that the company shipped to Hawaii for the test.

The company's entry into our shoot-out — a beta release of ControlCenter 5.1.2, which is promised to be generally available in October — proved to be a strong contender and is arguably the most comprehensive of all the vendor-specific management tools. Unlike IBM's two Tivoli products and HP's suite of five products bundled under the OpenView label, EMC's ControlCenter is a single control point, a unified user interface for administering one or more storage networks.

ControlCenter's administrative console gained reasonable visibility into the integrated storage network, though it fell short of gaining full information about the configuration of the competitive HP and IBM disk arrays because the company hasn't developed management agents for those devices.

Particularly impressive was EMC's ability to simplify storage management with a rich array of role-based wizards for storage allocation, event monitoring, performance management, and data protection and backup. From an administrator's perspective, ControlCenter makes it easy. It also has strong role-based access controls based on Microsoft's Active Directory authentication database.

EMC also stood out because, unlike any of the other vendors, it achieved a limited amount of true SAN integration — without deploying a virtualization server. ControlCenter performed storage zoning across the integrated SAN, tying together EMC's disk array and some of HP's storage hardware, which was an impressive performance.

Although there are many aspects of the ControlCenter application that we found compelling, one stands out. Its ability to show a complete view of a storage network topology, including a full visual trace of storage all the way from a particular server, through its HBA, through the FC fabric, to a disk array, to a specific slice of a disk was very impressive.

Overall, EMC's ControlCenter application is extremely strong; its well-unified graphical interface placed it nearly on par with Fujitsu Softek's SANview and ahead of IBM and HP. However, its reliance on agents and the limited support for competing hardware shoot it down as an integration solution for all but EMC-centric storage networks.

Hewlett-Packard

OV SAM (OpenView Storage Area Manager) 3.1, Hewlett-Packard's software management software, is a suite of five products that handle different aspects of administering a SAN: Storage Node Manager provides low-level control of specific network devices; Storage Builder helps with capacity management; Storage Optimizer tunes arrays for faster performance; Storage Accountant (which we didn't use in this test) tracks usage for billing purposes; and Storage Allocator handles access control and storage allocation.

The GUI-based OV SAM contains a CLI (command-line interface) familiar to Unix users; it's not unlike the CLIs used to control many switches, such as those from Brocade or McData.

That's good because OV SAM wasn't able to perform any active management functions across the combined SAN (no active zoning, no replication, no remote switch management). According to company spokespeople, some of that functionality will be added in a future version of the software suite. For now, OV SAM is limited to viewing and mapping the non-HP components — but even there, it had difficulties, as it wasn't able to gain much visibility into the configurations of the EMC and IBM gear.

We were disappointed at the limited level of administrative access controls in OV SAM. Basically, there are three levels of access: complete, complete except for the ability to change access control rights, and view-only. There's presently no way to limit or partition the scope and authority of individual administrators to specific tasks or devices. Again, that's a feature that HP says will be fixed in a future release.

Also disappointing was HP's Storage Optimiser, which doesn't optimise. It's a reporting-only tool that can display statistics about system performance but can't actually adjust or tune anything.

OV SAM may appeal to shops seeking to integrate multiple HP SANs with a common administrative interface. But frankly, that's about it.

To Virtualise or Not to Virtualise

The best solution to date, as demonstrated by Fujitsu Softek and IBM, is storage virtualisation, but that's a radical and intrusive solution that adds an extra level of abstraction to the network — and potentially adds a performance and reliability bottleneck. Certainly, the decision to flow all of an integrated enterprise storage network's traffic through a pair of virtualization servers is not one that should be made lightly.

Less invasive, software-based solutions, such as those from EMC and HP, are suitable for simplifying the administration of multiple storage networks; they can reduce the amount of effort require to manage disparate storage resources, but of course don't offer the benefits of consolidating storage into a single network.

As always, your choice will depend on system requirements. There are pros and cons either way. Nothing is simple when it comes to storage networking.

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