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The following cross-section of midrange NAS arrays was selected based on input from industry analysts and... More...

The U.S. Department of Energy (DOE) office that oversees research and development of renewable energy has brought in Atrato Inc.'s self-healing disk arrays to support a server virtualization project.

According to Tim Porter, acting network and operations manager, the DOE's Golden Field Office in Golden, Colo., originally planned to use an iSCSI SAN from Dell Inc. EqualLogic for the project, based on the assumption that iSCSI storage would be the most cost-effective option.

However, Porter said, in the department's environment with 50 virtual servers, the Dell EqualLogic PS5000 series array the DOE tested... More...

To try and persuade reluctant organizations to embrace the cloud, Iron Mountain and LiveOffice are offering hybrid cloud data archiving services that let customers keep data onsite while sending copies offsite for the vendors to store.

Iron Mountain is expanding its Digital Records Center for Medical Images service, while LiveOffice is archiving on-premise SharePoint data to its cloud storage.

Iron Mountain and Hewlett-Packard (HP) Co. launched the medical images service in early 2008, installing a gateway server at the customer site to move data from PACs (picture archiving and communication... More...

NetApp Inc. has unveiled design guides and capabilities to help service providers build cloud storage offerings.

The new NetApp solutions include the NetApp Service-Oriented Infrastructure (SOI), Data Protection as a Service (DPaaS) design guide, Backup/Recovery as a Service (BRaaS) design guide and NetApp Open Management to link IT services to NetApp's storage automation engine. Asigra Inc. is a partner for the BRaaS design guide — Asigra Cloud Backup software runs on the NetApp SOI.

Hewlett-Packard, IBM sell Emulex FCoE adapters

Emulex Corp. scored design wins with its OneConnect Universal... More...

Symantec Corp. is planning to pull together more intellectual property (IP) from its data storage and security businesses this year. The company says it will launch software in mid-2010 called Data Insight and integrate it with other products in the Symantec portfolio to link IT resources with data owners.

Other vendors have products that can provide this functionality, including data classification offerings from EMC Corp.'s Kazeon and StoredIQ and legal review products from e-discovery software vendors that track data according to case and custodian. Where Symantec is looking to get an edge on... More...

These are still early days for cloud storage, but we've already gleaned valuable best practices from administrators and other experts for getting the most from a move to the cloud, whether you're looking to do it today or down the road:

Best practice #1: Scrutinize service-level agreements

Proceed with caution when it comes to getting a service-level agreement (SLA) from a cloud provider. That means read the SLA closely before committing.

"There are a few major providers offering SLAs that are very vague about things like guaranteed recovery and assured destruction of data," Beth Israel Deaconess Medical Center (BIDMC) storage architect Michael Passe said at a Storage Decisions session last year. "You want to look behind the wizard's curtain to see what is really there."

Lauren Whitehouse, a senior analyst at Milford, Mass.-based Enterprise Strategy Group (ESG), said data access is one area that bears close examination in an SLA.

"Generally, SLAs have to do with access to the service, not to data," she said. "Generally, the service has to be down more than 10 minutes before it's considered an outage, so two nine-minute outages in an hour don't count as an outage. If there's an outage of the service, they just adjust the bill -- that's the kind of game that gets played. You have to ask, 'What about access to data?'"

Best practice #2: Follow your business needs

Lantmännen, a collective owned by 40,000 Swedish farmers, saved more than $6 million in the first year after building an internal private cloud with EMC Corp. storage and Riverbed Technology WAFS devices, said Dennis Jansson, Lantmännen's chief security officer.

Jansson said users choose what type of application they need through a web interface, and each service has a fee, SLA and integrated enterprise security management application.

"We're able to actually follow business needs," Jansson said of the cloud. "It doesn't make decisions on applications the users need."

He called the cloud "an easier way to say consolidation, virtualization and standardization."

Best practice #3: Repurpose your own resources

Online advertising sales rep firm Gorilla Nation Media LLC built an external customer-facing cloud and an internal cloud for employees by using servers it already owned along with cloud vendor ParaScale Inc.'s Hyper-scale Storage Cloud software to build an object-based clustered NAS system for unstructured data. Alex Godelman, vice president of technology at Gorilla Nation, said the cloud replaced a more expensive NAS setup.

"To grow the internal cloud, we just add more nodes," he said. "The design of the system is also very simple -- we just kind of use it. And it allows us to breathe some life into a huge existing investment, which means we created the system virtually for free."

Best practice #4: Prepare for the future

Even if you're not ready for the cloud now -- or the cloud's not ready for you -- start thinking about how it may help you down the road.

Charles Shepard, director of systems architecture at the MGM Mirage in Las Vegas, said he will consider an external private cloud when technology advances make it feasible.

"When Fibre Channel over Ethernet [FCoE] becomes completely adaptable and adopted over the next five years, and when it is completely standardized, that is the pathway to develop a full cloud outside our data center," he said. "If you have a big enough pipe, like 10 Gigabit Ethernet [10 GbE] or even 100 [Gigabit] Ethernet, you might be able to take a database and write from it to the cloud."

He said FCoE would be well suited to multitenancy, which is a crucial component of the cloud.

"It inherently subsegments networks for internal and external multitenant environments," he said.

Best practice #5: Beware of hidden costs

Cloud storage providers will tell you the basic cost per gigabyte of cloud storage up front to help you figure out how much it will cost you per month depending on the amount of data you need to store. But these basic costs are only part of the picture, and providers may also charge extra for data transfers, metadata functions, or copying and deleting files. And don't forget the costs of connecting to the cloud, perhaps with a T1 line.

For more on cloud storage:

1. Find out why the evolving cloud storage market has users weighing their enterprise data storage options

2. Discover why external cloud storage appeals to smaller firms, but large enterprises remain cautious

3. We explain how internal private cloud storage makes its way into larger enterprises

4. Read why not everyone thinks the future is bright for clouds Learn best practices for getting the most from cloud storage, including what to look for in a service-level agreement (SLA), using existing resources to set up a cloud and how to avoid hidden pricing.

The iSCSI storage-area network (iSCSI SAN) has been discussed and debated for much of the last decade, but iSCSI has finally come into its own as a networked storage underpinning for virtual server environments, analysts say.

Enterprise data storage vendors such as Hewlett-Packard (HP) Co.'s LeftHand Networks and Dell EqualLogic have cited the additional costs of networked storage requirements as a barrier to server virtualization adoption for some customers in positioning iSCSI SAN products for that purpose, and tout the relatively low cost of iSCSI SANs compared with Fibre Channel (FC). But according to Jeff Boles, senior analyst and director, validation services at Hopkinton, Mass.-based Taneja Group, there are some technical considerations that make iSCSI more appealing for virtual servers as well.

"A lot of engineering went into Fibre Channel based on the assumption of one host per port," Boles said. "iSCSI has virtualized access anyway, over an IP connection, and has had more engineering around multiple-host contention and various queuing patterns."

While Ethernet networks and the basic best practices for iSCSI SANs are generally well understood by now, if you're looking to deploy an iSCSI SAN to support server virtualization, experts say there are some different factors to keep in mind than when connecting physical servers via iSCSI. Here are five best practices for using iSCSI in a virtual server environment.

Best practice #1: Look beyond basic iSCSI

In the years since iSCSI first came on the scene, products have had time to mature and develop, adding specialized features along the way. In the meantime, iSCSI-related products have proliferated to the point where software-based iSCSI initiators and targets can be had completely free of charge. iSCSI SANs can be built using commodity server hardware and open source software as well.

But Boles said iSCSI specialists, like HP's LeftHand or Dell EqualLogic, are charging a premium for advanced features such as integrated VMware snapshots. Other iSCSI SAN vendors, such as EMC Corp. and NetApp Inc., offer unified storage arrays with various options for connecting servers, including iSCSI. Disk arrays from storage specialist vendors also often have features like quality of service and virtual machine-aware management consoles.

The iSCSI network these arrays are attached to can also make a difference, Boles said. "If you have the right infrastructural underpinnings, for example a well-built, fully managed Cisco environment, you can apply more sophisticated and granular policies to virtual servers."

On the other hand, some of the most advanced iSCSI deployment methods aren't really necessary for a virtual server environment where cost and consolidation are primary factors in purchasing decisions, countered Greg Schulz, founder and analyst at Stillwater, Minn.-based StorageIO Group. As data grows and 10 Gigabit Ethernet (10 GbE) looms on the horizon, some industry experts see technologies like TCP/IP offload engines (TOE cards) coming into play.

But users should balance the availability of these performance enhancers with their original rationale for deployment, Schulz said. "If low cost is the reason I'm deploying iSCSI, I'm probably not going to invest in hardware adapters. Instead, I might want to enable jumbo frames and quality-of-service features through software."

Best practice #2: Consider where iSCSI targets should live in the virtual environment on an application-by-application basis

For VMware environments specifically, "It used to be users had to make a tough choice," Schulz said, between VMware's clustered file system (VMware vStorage VMFS) or raw device mapping (RDM). Before Version 3.5, VMFS offered features like VMotion, but RDM was sometimes the only way to continue to use value-added features of storage arrays like snapshots and virtual provisioning.

While this is no longer the case today, Brian Garrett, vice president of ESG Labs at Milford, Mass.-based Enterprise Strategy Group (ESG), said users should still evaluate where to place the iSCSI target in the infrastructure for performance and manageability reasons. They have a choice of deploying the target as either a virtual disk at the hypervisor level, allowing the server virtualization software to handle calls to the back-end storage through a virtual hard disk layer; or at the disk array, providing somewhat speedier block-based access to the back-end storage.

"The decision will depend in part on what you're already used to," Garrett said. "But block-based apps like SQL databases, for example, work well with raw disks, and would probably be suited to the pass-through or raw mode."

Best practice #3: Rethink network and cabling designs

"One thing users often don't think about is the way iSCSI can give you freedom from past paradigms," Taneja Group's Boles said. Storage pros are used to the Fibre Channel world, where a monolithic disk array is attached via a complex series of switches and cables to servers in a separate aisle of the data center.

With an increase in scale-out and commodity-hardware-based iSCSI SAN architectures, Boles said a new networked storage deployment might also be a good opportunity to rethink the data center layout. "With some of these iSCSI systems, you can interleave the storage with the server farm, and get the storage closer to the server environment without as many long cables."

Rethinking the physical placement of resources in the data center can help resolve issues with overloading parts of the network. "You don't have to shove I/O down a big trunk and then fan-out to the entire infrastructure – interleaving can avoid these bottlenecks," he added.

Best practice #4: Be mindful of monitoring

Boles and Garrett both emphasized that the new virtual world requires new virtualization-aware monitoring tools throughout the data center infrastructure, particularly as highly portable virtual machines (VMs) move around the network. "When you get into a virtual environment, performance monitoring and tuning become a lot more important," ESG Labs' Garrett said. "In the physical world it was easier to make sure you had the right number of actuators to avoid overconsolidating and violating basic storage guidelines."

Added Taneja Group's Boles: "It's easier to implement monitoring from Day 1 than to go back and retrofit a network fabric with monitoring tools; make purchasing decisions with this in mind."

Best practice #5: 10 Gigabit Ethernet remains a ways off

The next boost in Ethernet bandwidth will probably improve iSCSI performance and offer more network consolidation opportunities within data centers, and the transition to 10 Gigabit Ethernet will begin imminently, according to Rick Villars, vice president, storage systems and executive strategies at IDC in Framingham, Mass. "This will be the year server vendors tell people to go to 10 Gigabit Ethernet," he said.

But Villars urged caution when it comes to porting iSCSI SANs to 10 GbE networks too soon, particularly if you're dealing with implementing a virtual server environment already. "You have to decide whether iSCSI is the first or the last thing you want to bring on [to a new 10 GbE network]," Villars said. "Since it's in the early stages, I wouldn't want to go out and start with an iSCSI SAN on [10 GbE] yet." Storage experts offer best practices on how to maximize iSCSI SAN performance and efficiency in virtual server environments, where the protocol has found its biggest audience.

No matter how much storage capacity you squeeze into an array, it's just a matter of time until that space is completely filled. Users everywhere are challenging existing storage resources with applications that proliferate media-hungry data files. This is where SAN expansion technology comes in.

This handbook takes an in-depth look at SAN expansion technology and offers advice on the many elements involved, such as integrating SAN and NAS, switch upgrades, disk array replacement and capacity planning tools.

Best Practice No. 1: Expanding or replacing disk arrays
Even the biggest disk array eventually runs out of storage space. Tiered storage? Data deletion? No matter. At some point, you'll still need to expand or replace your SAN. Here are eight best practices for disk array expansion or replacement.

Best Practice No. 2: Switch upgrades and replacements
Switches must provide a mix of performance, reliability and management versatility, while maintaining a reasonable cost per port. Here are eight best practices for switch upgrades and replacements.

Best Practice No. 3: Host bus adapter upgrades and replacements
Learn how to maintain control over HBA selection, eliminate bottlenecks, boost availability and how HBAs will interact with FCoE. Here are seven best practices for host bus adapter upgrades and replacements.

Best Practice No. 4: Selecting a storage capacity planning tool
To select a storage management and capacity planning tool, first calculate how much storage is available and how much of your total storage capacity is actually being used. Here are eight best practices for switch upgrades and replacements.

Best Practice No. 5: Integrating SAN and NAS
SAN and NAS platforms are often interconnected so their respective benefits can be pooled. However, storage administrators must take care when connecting SAN and NAS. Here are eight best practices for integrating SAN and NAS.

Best Practice No. 6: Integrating iSCSI and Fibre Channel, and make it work
Although companies of every size are embracing iSCSI SAN technology because of its lower cost and relative simplicity, there are situations where iSCSI and Fibre Channel coexistence makes sense. Here are eight best practices for integrating iSCSI and Fibre Channel technologies.

Best practices for SAN expansion include options for integrating SAN and NAS or iSCSI and Fibre Channel, evaluating capacity planning tools, as well as upgrading switches, disk arrays and HBAs.

What you'll learn: For organizations hoping to achieve information lifecycle management (ILM) goals, finding a solution that meets their specific policies, processes and practices can be difficult. Learn how tiered storage tools can help organizations meet these goals in a cost-effective and practical way.

By assigning different categories of data to different types of enterprise data storage media, tiered storage tools aim to reduce overall storage costs. While tiered storage is not a complete information lifecycle management solution, it does play an important role in a successful ILM hierarchy. As one vendor puts it, "ILM is all about having the right storage at the right time at the right cost."

For tiering data within a storage array, 3PAR Inc., EMC Corp. and Hitachi Data Systems (HDS) Corp. all offer a LUN virtualization component, which allows data stored on high-performance disk to be migrated online to lower-performance disks and vice versa based on pre-set policies and I/O patterns.

All three of these storage vendors support some sort of online LUN migration technique and all require a separate piece of hardware or a virtual machine (VM) that monitors the storage and initiates LUN migrations based on pre-set policies.

On the software solution side, 3PAR implements storage tiering through its Utility Data Lifecycle Management (DLM) product. Utility DLM uses templates, virtual copy and remote copy services to migrate data between tiers on the array both locally and remotely. The Utility DLM software can run on a Linux or Windows workstation, and all of the heavy lifting occurs on the array.

For EMC's Virtual LUNs, data can be seamlessly migrated between RAID levels and disk types. The Virtual LUN technology can be managed by EMC's Symmetrix Control Center (SCC) if the customer is using a Symmetrix V-Max. EMC's Fully Automated Storage Tiering (FAST) or its Navisphere Management Suite (NMS) for the CLARiiON line can be used to manage the virtual LUN migration based on policies and data access patterns for the Clariion CX-4 line. Both SCC and NMS require Windows hosts.

Hitachi also has a software-based tiering solution simply called Tiered Storage Manager, which supports LUN migration between tiers in a virtualized storage pool. The pool can include other vendors' arrays attached to the Hitachi USP storage array platform.

External tiered storage tools include IBM's SAN Volume Controller (SVC), EMC's Invista and Hitachi's USP-V.

SVC is an xSeries based "I/O engine" architecture that acts as a front end to all SAN storage. The SVC can front-end any Fibre Channel-attached storage array regardless of vendor and can provide iSCSI connectivity on the front end as well as Fibre Channel (FC). LUNs can be seamlessly migrated within and across back-end arrays, allowing customers to provide one vendor for Tier 1, another for Tier 2 and so on if their environment dictates heterogeneous storage.

EMC's Invista also utilizes external nodes, but the twist is that it also uses an intelligent SAN switch (or linecard), and each LUN on the back-end array has a virtual address that is presented to the host. EMC considers this solution to be operating at Layer 2 in the Open Shortest Path First (OSPF) model and is touted as "network-based volume management."

Hitachi's USP-Vis the company's high-end line of storage arrays; the LUN virtualization occurs within the storage controllers and does not require any external components. Typically, customers include the Hitachi Hi-Command server, which is comparable to EMC's NMS or SCC. Hi-Command and the Tiered Storage Manager software are required for LUN migrations, and these migrations can be performed between arrays online with no disruption to hosts.

All of the tools discussed have been SAN infrastructure-level components and can certainly be considered ILM. All of the tools are policy-based, either by application requirements, age requirements or cost requirements; all are storage-centric; and all support live data migration in a transparent way. To be successful, storage tiering tools should have as little impact as possible on the user's experience, and the storage vendors are clearly showing that they can provide this service to aid IT in its pursuit of ILM. Tiered storage tools can help organizations meet information lifecycle management (ILM) goals. Learn about the internal and external tiered storage tools available from 3PAR, EMC, HDS and IBM.

Almost every major data storage vendor, including EMC Corp., Hewlett-Packard (HP) Co. and IBM, is incorporating flash memory into their storage arrays in the form of solid-state drives (SSDs). Yet many enterprise data storage managers are hesitant to use flash-based SSDs because they're not sure where to use them or how to justify the expense.

To begin, some IT managers have trouble even placing SSDs, also referred to as NAND flash, in the technology stack. "They have to think of it like storage cache that's faster than hard disk storage but slower than DRAM," said Jim Handy, SSD analyst at Los Gatos, Calif.-based market research firm Objective Analysis.

The high price also poses a problem. "The cost of NAND flash collapsed in 2009," Handy said. On average, he figures SSD is still 20 times more costly than hard disk storage on a cost-per-gigabyte basis, although prices are expected to continue to drop.

However, if you look at SSD in terms of cost per input/output operations per second (IOPS), the cost equation looks decidedly different. According to Mark Teter, chief technology officer (CTO) at Advanced Systems Group (ASG), "flash is almost 140x faster than the fastest HDD [hard disk drive]. To match the performance of flash using HDDs you would need to aggregate the output of many HDD devices."

As it turns out, a little NAND flash goes a long way. Teter often recommends organizations add some solid-state drives for their high-performance workloads and use low cost, slow Serial ATA (SATA) for everything else.

Still, enterprise data storage managers can't just throw SSD into the storage mix. Most storage controllers will be quickly saturated by an SSD. "The current crop of storage controllers can only handle a limited amount of disk IO. A flash drive as storage will easily swamp today's controllers," Teter noted.

Flash-based SSD uses: caching tier for servers or storage tier

But when you deploy a small amount of flash storage in the right place at the right time and for the right application, flash produces dramatic reductions in the cost of performance as measured in IOPS.

There are currently two general uses for flash-based SSD in the enterprise IT stack: as a caching tier for servers or as a storage tier. Teter currently recommends the use of flash for dedicated caching since it offers more efficiency and flexibility.

The best way to take advantage of this is through a file system or caching appliance, such as Storspeed Inc.'s SP5000 NAS caching appliance, Dataram Corp.'s XcelaSAN, Gear6 Inc.'s Cachefx appliance or Avere Systems Inc. FXT Series.

Conventional file systems generally don't work well with flash storage. The exception is the latest Linux kernel. "The Linux 2.6.30 kernel is chock full of next-generation file systems, including NILFS [New Implementation of a Log-Structured File System] that's showing great promise with SSD drives. At ASG, we've been testing NILFS," Teter said.

By using flash as a caching tier, it can work directly with next-generation host file systems that already know what to do with it. Here, flash can provide application performance acceleration; at a minimum, you could put indexes on flash to boost database performance.

Four ways to use flash storage

Given the price and performance advantages of flash, Teter suggests four ways to use flash in the enterprise IT storage stack today:

As cheap IOPS. Organizations that need high performance for processing transactions or other high-volume work requiring top performance can use a few flash units to replace multitudes of underutilized high-performance hard disk drives.

Swapping costly HDDs for low-cost HDDs for most applications. Replace most of your costly, high-performance HDDs with lower cost, slower, but still adequate HDDs while using a small amount of flash as cache for those few applications that require truly high performance.

To get extreme performance at increasingly lower costs. Where organizations need extreme performance, or where they need to differentiate themselves and gain a competitive advantage through performance, they can use SSD flash instead of conventional HDDs. If cost per IOPS is critical, SSD flash will give them the lowest cost per IOPS now, and it will only get lower in the future.

For significant green storage savings. Enterprises constrained by power availability or those facing high energy costs can replace energy-intensive HDDs (especially in performance situations) with a mix of flash -- which consumes far less energy -- and lower performance, large capacity SATA drives, which use less energy than high-performance HDD.

Solid-state drives have the potential to replace high-performance HDDs. At that point, storage managers can use low cost, slower SATA HDD for the bulk of their mass storage needs and deploy SSD where performance is an issue.

BIO: Alan Radding is a frequent contributor to TechTarget sites. We tell you how the combination of flash memory and SSDs can help your organization achieve higher performance levels, cut storage costs and improve green storage initiatives.

What you'll learn: MAID and intelligent power management (IPM) are green storage options that align enterprise data storage performance and energy consumption levels. Find out what you should look for in a product with MAID or IPM-enabled capabilities.

There's a myth in the enterprise data storage industry that massive array of idle disks is a dead technology, but MAID is still an effective green storage option. Many data storage vendors offer MAID 2.0 technologies through a variety of names or aliases, such as drive spin down or intelligent power management (IPM).

Vendors that currently provide some type of MAID 2.0 or IPM-enabled product include Adaptec Inc., DataDirect Networks Inc., EMC Corp., Fujitsu Ltd., Hitachi Data Systems, NEC Corp., Nexsan Technologies Inc., Sun Microsystems Inc. (now owned by Oracle Corp.), Xiotech Corp. and Xyratex International Inc.

Like other storage technologies, some MAID vendors like to have their own naming conventions to differentiate their products from those of their competitors. For example, IPM essentially aligns enterprise data storage performance and energy consumption to match applicable service levels. Regardless of the naming convention, IPM is still an approach to saving on energy consumption by powering down hard disk drives (HDDs) when not in use.

Boost performance when needed, conserve energy during slower periods

The most common issues I regularly encounter with MAID are concerns around performance and a lack of configuration flexibility. Some first-generation MAID products saved power at the expense of performance, were expensive to deploy and lacked scalability. But there's an expanding awareness that energy efficiency not only includes avoidance, but also means boosting performance when needed and conserving energy at other times.

What this means is that a shift from first-generation energy avoidance at the expense of performance or productivity is now occurring for both servers and storage. For example, servers and their processor chips with IPM-enabled technologies, such as the Intel Nehalem, can boost performance when needed, then turn cores off or run them at lower clock speeds during slower periods to conserve energy.

What to look for in MAID and IPM-enabled products

When and where to use MAID technology and IPM-enabled products will depend in part on what a specific product supports in terms of feature functionality. There are extensive deployment options for products that support high-performance disk drives with the flexibility and software support to manage logical unit numbers (LUNs), volumes or file systems appearing/disappearing during power down periods.

Other good candidates include near line, bulk reference, online archive and other data on applications that can tolerate a response time or latency pause when a disk needs to be spun up.

Here's what you should look for in a product that has MAID 2.0 or IPM-enabled capabilities: Can different power or energy-usage-to-performance settings be enabled?
What's the granularity of the power savings? Is it on a LUN, volume, volume group, virtual array or physical array basis?
Can power management be enabled for different types of disk drives, such as Fibre Channel (FC), high-capacity serial ATA (SATA) or solid-state drives (SSDs)?
What's the transparency to path managers, file systems, volume managers or databases when a disk, LUN or volume is spun down?

It's also important to find out if additional fees for capabilities like RAID are part of the standard price of the product, if there are performance impacts when accessing data, and if there are data integrity safeguards and checks to ensure that the system is functioning properly.

Finally, look for next-generation MAID-enabled capabilities to appear in many more storage products, including NFS and CIFS appliances, iSCSI, SAS, FC and Fibre Channel over Ethernet (FCoE) offerings.

BIO: Greg Schulz is founder and senior analyst at StorageIO Group in Stillwater, Minn. MAID and intelligent power management (IPM) are green storage options that align enterprise data storage performance and energy consumption levels. Learn what you should look for in a product with MAID or IPM-enabled capabilities.

Aside from a few failed attempts from other vendors, Brocade Communications Systems Inc. and Cisco Systems Inc. almost exclusively own the Fibre Channel (FC) director switch market.

With much in common between the Brocade DCX Backbone and Cisco MDS 9500 offerings, including pricing, the most important director switch selection criteria are which platform fits best into your existing infrastructure and which vendor's strategy aligns more closely with your roadmap.

Latency, throughput and oversubscription comparison

The Brocade DCX Backbone and Cisco MDS 9500 Series are both chassis based, can be scaled and present no single point of failure and support all relevant storage networking protocols.

The DCX Backbone is available in two modular form factors: The 14U Brocade DCX Backbone built for large enterprise networks and the Brocade DCX-4S Backbone built for midsized networks.

Cisco offers three MDS 9500 models: The MDS 9513, supporting a record 512 8 Gbps FC ports, is targeted at enterprise networks. For smaller networks, Cisco offers the MDS 9509 featuring nine slots, and the MDS 9506 with six slots.

While both the Cisco and Brocade platforms can be used to power mission-critical storage-area networks (SANs) with comparable results and user experience, there are noticeable differences between the two.

The DCX Backbone supports local switching, which results in lower latency for devices connected to the same blade and improved scalability by reducing the amount of traffic that has to pass through the core switching blades.

Although Cisco rebuffs the local switching benefit, emphasizing bigger latency variances as a result of local switching, support for local switching in its latest Nexus platform suggests that the lack of local switching support in the MDS 9500 is a disadvantage.

In addition to reliability, performance and throughput are the most relevant attributes of a director platform. The Brocade DCX Backbone currently wins the raw throughput comparison with 256 Gbps throughput per slot vs. 96 Gbps for the Cisco MDS 9500.

Despite claims that both platforms require less SAN architecting, each director platform has idiosyncrasies a SAN designer needs to consider. The SAN design effort of the MDS 9500 will likely be related to managing oversubscription and traffic prioritization. Correspondingly, the DCX Backbone requires SAN architects to take latency variances between different ports within the same chassis into account.

Feature comparison

Brocade DCX Backbone

Cisco Systems Inc. MDS 9500

Models

*DCX Backbone (eight port blades)
*DCX-4S Backbone (four port blades)

*MDS 9513 (11 port blades)
*MDS 9509 (seven port blades)
*MDS 9506 (four port blades)

Maximum port count

384

512

Bandwidth per slot

256 Gbps

96 Gbps

Biggest benefit

Fastest Fibre Channel (FC) director on the market. Significant lead in the total number of FC ports sold.

High degree of investment protection, long product lifecycle and coherent product line that uses the same NX-OS operating system

Fibre Channel over Ethernet (FCoE) support

Will be available once the standard is ratified

Available now via the Nexus 5000 switch; for the MDS 9500, Nexus 2000 and Nexus 7000, it will be released on standard ratification

Fibre Channel over Ethernet and CEE/DCE support

Compelled by the prevalence of Ethernet and its enhancements, and the success and simplicity of iSCSI, Brocade and Cisco have embarked on bringing Ethernet into the well-guarded FC domain via Fibre Channel over Ethernet (FCoE). FCoE uses Converged Enhanced Ethernet (CEE) -- Cisco calls it Data Center Ethernet (DCE) -- as the physical network transport to deliver Fibre Channel payloads. However, unlike its Ethernet brethren, it's lossless and appears as native Fibre Channel to the operating system and apps. Unlike iSCSI, it's not routable and is designed as a low-latency, high-performance Layer 2 data center protocol.

Both Brocade and Cisco are committed to FCoE, but each one has its own FCoE strategy. Brocade won't ship Converged Enhanced Ethernet products until the standard is ratified; at that point, Brocade will support FCoE and CEE in its DCX Backbone via new blades. Older Brocade Fibre Channel products, such as the 48000 Director, will connect through the DCX Backbone or a new top-of-rack switch to interface with CEE components.

With the Nexus 5000 Series top-of-rack switch, Cisco is the first vendor to offer a pre-standard FCoE product. For the MDS 9500 director family, as well as the Nexus 2000 Series Fabric Extenders and Nexus 7000 Series switches, DCE and FCoE support won't be available until standard ratification, similar to Brocade's plans.

Regardless of whose product you choose, both platforms will reliably power your SAN, which is confirmed by the myriad storage-area networks currently powered by Brocade and Cisco. Both vendors are embracing the converged Ethernet paradigm in their product roadmaps, but unless you're willing to debug the initial CEE/DCE flaws as an early adopter, you're well advised to wait for at least another year until the standard and products have matured.

This article originally appeared in Storage magazine. Are you looking for director switch for your SAN? We compare the Brocade DCX Backbone and Cisco Systems MDS 9500 offerings in terms of latency, throughput and FCoE support.