Evolving SANs require new management tools

Posted on August 01, 2001

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Large shifting SANs require configuration comparison, asset/change/service management, and replication capabilities.

BY ANDREA DAHLBERG

Due to rapidly evolving technology, storage area networks (SANs) are continually being updated with hardware, software, firmware, drivers, patches, and service packs to optimize performance, increase capacity, or address interoperability issues. A well-constructed SAN may start exhibiting problems when just one of the devices is updated or removed. In fact, simple changes made in an effort to optimize a SAN configuration can often backfire, initiating a domino effect that could bring down a significant portion of the SAN, if not the entire network.

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To exacerbate matters, anomalies within the SAN can manifest days or weeks even after a simple change has been made. Suddenly, a device doesn't respond or a component/link starts exhibiting poor performance. How is a storage administrator notified of the problem before it becomes a crisis? Once notified, will he or she be able to identify the changes made to the SAN so that the source of the problem can be located and corrected? How will he or she determine when the changes were made and by whom? SAN system vendors and their customers will benefit from management tools that can help "undo" problems by returning the SAN to a previously healthy configuration.

A seemingly unrelated yet important problem occurs when large enterprises need to replicate well-tested SAN configurations in multiple locations. They require a management tool that enables duplicate SANs to be installed and deployed without requiring the painstaking effort of ensuring that all SAN configuration details are identical to the tested configuration. How does a storage administrator encapsulate all the details of a healthy SAN so that it can be precisely re-created? To be successful, he or she will need to compare the details of the SAN components all the way down to the port level. Tools that support this challenging task will enable enterprises to realize return on their IT infrastructure much more quickly.

IT managers are also concerned about return on investment. As the complexity of the SAN grows, so does the amount of time it takes for administrators to track inventory and assets, taking them away from their core expertise of managing the availability of the SAN. This redirection of effort limits a company's sustainable gigabytes-per-manager ratio and negatively impacts its SAN return on investment. A management tool that transparently captures an inventory of the SAN anytime a change was made would allow precious cycles to be freed up. As a result, organizations can maximize IT staff effectiveness while maintaining service quality and lowering their SAN cost of ownership.

There is a pressing need for a new breed of storage network management tools to solve these configuration problems. These tools allow the status of the SAN configuration to be captured at any point in time-either manually or automatically. The configuration information is used for comparison, historical reference, change management, asset management, and troubleshooting. Users should be able to define what objects or devices to include in the capture, as well as specify what device details to capture-such as a device's firmware and serial number. Users should also be able to capture and track other important SAN details such as LUN information, zone configuration, and worldwide node name.

SAN management tools

Large shifting SANs require the following management tools:

Configuration comparison-Generating a baseline configuration allows a future SAN configuration to be compared to the baseline so that changes can be instantly detected. The comparison of two configuration captures makes it easy to spot changes in low-level device information or SAN parameters. Additions and deletions of SAN devices as well as changes to existing SAN devices are flagged. These changes are represented graphically and via a textual report. Visual cues direct administrators to the areas where changes have been made. The textual report provides specific details on what was added, deleted, or modified.

The ability to compare two different configurations of the same SAN can be a powerful troubleshooting tool. SAN administrators are too familiar with the countless hours spent reloading software and drivers on devices to fix elusive problems that plague complex software and hardware environments. SAN management tools can reduce SAN downtime along with associated service calls and technical-support costs.

Asset management-Configuration captures provide an automated way for administrators to manage SAN assets. Automating the collection of information on all assets frees administrators from the manual, time-consuming, and error-prone process of tracking assets. Time spent by administrators on low-level administrative activities takes away from their ability to keep the SAN well-tuned, optimized, and in a state of high-availability. Software tools that enable IT organizations to further leverage their support staff will allow companies to maintain more gigabytes of data per storage administrator, resulting in better return on SAN investment.

Change management-Many IT organizations manually keep logs of revisions made to their infrastructure. However, these procedures may not be followed for seemingly insignificant adjustments. When properly implemented, a change management process ensures tight control over all updates made to the SAN. However, it can also slow down and inhibit the application of routine maintenance. A software tool that automates the logging of SAN configuration changes can simplify the process because the risks associated with making modifications will be alleviated if they are automatically tracked. And the change process can easily be tailored to allow for automated logging, which enhances routine maintenance. Automatic logging also ensures that IT personnel closely follow a set process, because all revisions can be audited and tracked. A change management process ensures that configuration changes-including the name of the individual who made the change and the respective date and time of the event-made to a SAN are automatically logged in detail. The result is a better-managed SAN with higher levels of availability.

Replication-A common scenario when deploying a complex SAN configuration is to test a standard configuration in a controlled lab environment prior to deployment. In larger organizations, it's common for the lab configuration to be replicated in several locations. The discipline of carefully controlling the hardware and software configuration-even down to the firmware levels on hardware devices-can significantly decrease the support costs of these systems. This practice also decreases the cost of spare-part inventory, as fewer components need to be stocked if configuration control is maintained.

As SANs continue to evolve in complexity, software tools that allow a desired (lab-controlled) SAN configuration to be accurately replicated will enable SANs to be better serviced and supported when they are deployed. These tools simplify SAN replication with import and export utilities that allow configurations to be compared for accuracy. They also provide device-specific information such as firm ware and software driver versions.

Service management-Storage vendors' support organizations face unique problems in maintaining and servicing SANs. The level of control that vendors have over the maintenance of the SAN once it has been deployed is greatly reduced.

Shortly after the SAN has been deployed and successfully tested, control is relinquished to the customer. Problems may arise at a later time because the storage vendor has no guarantee that the customer has kept a careful record of all the changes that have transpired in the SAN over the period between support calls.

As SANs become more widely deployed, standard configurations will be sold and supported by large systems and storage vendors. Some storage vendors have adopted the approach of completely restricting customer access to the system, wherein all unauthorized changes made to the SAN are automatically reported to the support organization. Once these types of messages are received, the vendor dispatches support personnel to the customer site to return the configuration to its previous state, billing the customer for the service call. This practice will not be popular as SANs become more open, commonly deployed, and easier to manage.

Systems and storage vendors need new software tools that will allow a more cooperative-and less costly-approach to resolve problems. These tools should track changes and allow healthy and dysfunctional SAN configurations to be tracked and easily rolled back, if necessary. As a result, systems and storage vendors will be able to clearly convey the types of changes they will support as part of their service agreement, while also providing customers with the ability to maintain accurate information on changes made to their SAN.

Extensibility-SAN complexity continues to grow as hardware vendors deliver larger and faster devices ranging from switches and directors to host bus adapters, routers, and storage subsystems. SAN management software should easily accommodate the rapidly expanding list of hardware devices in the SAN. Many devices support standard APIs and MIBs such as the Storage Networking Industry Association HBA-API; however, some devices may not provide all of the information outlined in the standard, while others may provide more information. Therefore, it's important that SAN management software address additional SAN devices through an API that enables rapid support of additional hardware devices.

As SANs continue to grow in size and complexity, there is an increasing demand for management tools that can track SAN configuration changes and allow for quick and easy comparison between current and previous configurations, thereby enabling the rollback of a SAN-gone-bad to a known working configuration. There is also a need to accurately replicate SANs across multiple sites and to provide accurate data for detailed inventory and asset management. Armed with tools such as these, SAN managers and system vendors' help desks will be able to successfully aid businesses in achieving maximum return on investment in constantly evolving multi-vendor SAN environments.

Andrea Dahlberg is senior product manager at Prisa Networks (www.prisa.com) in San Diego, CA.

SAN management checklist


  • Configuration comparison
  • Asset management
  • Change management
  • Replication
  • Service management
  • Extensibility

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