INTERCONNECTS
SANity check
By Jim Metzler, Network World, -- Survey says SAN usage growing, but performance problems and lack of management tools are a concern. A long with any new technology come large doses of hyperbole and vague promises. With storage-area networks the promises included better ROI through storage consolidation and increased business productivity through collaboration. Now that SANs have been in place for a while, it's possible to step back and assess the scope of SAN deployment and gather some insight into how SANs are being designed to support business applications. Ashton, Metzler & Associates recently surveyed more than 100 IT professionals from a variety of companies, including Global 2000 corporations, government agencies, regional utilities, midsize businesses and universities. One common finding emerged: SANs have begun living up to the hype.
One of the key survey results is that SAN use is steadily increasing. The majority of companies surveyed have deployed at least one SAN, and roughly a quarter have deployed five or more. Also, while the first wave of SAN deployment was usually based on fabric switches, which had few ports and were not terribly robust, that situation is changing. Today, more than 40% of companies have a director-class switch, featuring 128 or more ports and a high-availability design.
Another key indicator of SAN acceptance is that companies that have already deployed SANs are planning to increase their usage significantly. Tom Harrold, systems architect at Information Resources, says that over the past few years his company has moved every device in its open systems environment that requires external storage onto a SAN. His company moved to a SAN environment to gain flexibility in assigning storage in response to rapidly changing business requirements.
Michael Boykins, director of technology infrastructure at Outback Steakhouse, adds that the only applications he runs on a SAN are database applications. However, he says over the next two or three years Outback will bring all its applications onto a SAN to enable the company to beef up its disaster-recovery capabilities.
Application brownouts
While SANs are continuing their march toward mass-market adoption, they still have a significant growing pain to overcome: application brownouts. The phrase refers to having one or more applications occasionally perform notably slower than usual and then self-correcting. Some indications of application brownouts include the help desk receiving calls that an application is taking longer than usual to run a report, or an administrator noticing that a backup is taking longer than usual.
Roughly 70% of companies that have deployed a SAN reported having an application brownout at least once a month, and almost half of the companies that were surveyed indicated they did not have a good handle on what caused the brownouts.
Boykins says that although current technologies don't let him prove it, issues in the storage network often lead to application brownouts.
Harrold agrees, noting there are no tools that give him the visibility he needs to trend SAN performance.
The source of the problem could be anywhere, including the SAN, WAN, server, database or application server. One customer interviewed for our survey suspected that the SAN was at least occasionally the problem. The thinking was that with many server ports trying to gain access to fewer storage ports, the SAN has some built-in bottlenecks.
The typical response when application brownouts occur is to add bandwidth.
Application brownouts have a significant effect on business, primarily through lost productivity within a business unit. However, more than a quarter of the survey respondents indicated that application brownouts also result in lost revenue. More than 30% said the effect of an application brownout was significant or very significant, with more than half of the respondents indicating that if their company's ERP application experienced a brownout, the impact would be significant or very significant.
Harrold adds that if his company's ERP application experiences a brownout it can lead to delayed deliveries to customers. In addition to engendering ill will, these late deliveries also can result in financial penalties.
In terms of buying criteria, the survey showed that the most important items were reliability, availability, serviceability and scalability. At the low end were storage vendor recommendations. Initial cost of a SAN scored somewhere in the middle of the pack.
Because cost is typically a relatively unimportant factor in the selection of an emerging technology, and a very important factor in the selection of a legacy technology, the study results indicate that storage networks have moved out of the innovator phase and into a more mainstream adoption phase.
Harrold says that based on his experience developing a SAN environment, interoperability is his most important decision criteria, followed by management issues such as being able to monitor the performance of inter-switch links (ISL) and switch ports.
One of the characteristics of a mature marketplace is that customers tend to have a preferred provider. That is not the case with SANs, where the current base of SAN users is not tethered to their existing storage network vendors. Furthermore, users are reducing their reliance on storage vendors to recommend their storage network infrastructures, indicating that they feel more knowledgeable about SANs. This indicates a more experienced and independent market.
Also, companies are beginning to run their business-critical applications over a SAN. More than three-quarters of the respondents indicated that their company's ERP and CRM applications are SAN-attached. The fact that companies are now running these applications over a SAN helps explain why reliability, availability and serviceability are the most important decision criteria.
Data center changes
One of the key drivers in the current wave of SAN deployment is the extent of change taking place in the data center. The majority of survey respondents indicated that their company had made at least moderate progress with consolidation projects such as data center consolidation, storage consolidation and server consolidation.
Changes in the data center are going to continue and will further fuel the deployment of SANs. The majority of companies that have already embarked on consolidation projects and expect to consolidate more in the next 12 months. Boykins and Harrold agree that the major change in their company's data centers has been server consolidation. According to Harrold, over the last three years his company has reduced the number of Unix servers by 30% and is now starting a similar activity focused on Windows-based servers.
SAN architectures also are changing. Stories on best practices in SAN design typically discuss the use of a "core-edge" design. While there is some indication that this design might become the industry norm, it is not yet widespread. Roughly 30% of the survey respondents indicated that they virtually always implement a core-edge design today, with almost 40% reporting that they will implement this architecture a year from now. The survey respondents also indicated that they do not tend to oversubscribe their ISLs, particularly in the case where a SAN is supporting a business-critical application such as ERP.
Harrold says that a couple of years ago his company had isolated SAN islands each built around a director-class switch. His company has since moved to a core-edge design, with director-class switches deployed at the edge and at the core.
Based on the findings of this study, SANs have clearly moved out of the early adopter phase. Storage networks are large and getting larger. They are supporting more key applications, and finding value in consolidated storage environments. Buyers are becoming more discriminating, implementing more sophisticated architectures and selecting storage network products based on their unique technology requirements.
However, there also are some unresolved issues surrounding SAN deployment, including the widespread occurrence of costly application brownouts and the lack of effective management tools. As SANs continue toward mass-market adoption, users and vendors should take a moment to think about the needs for next-generation, ubiquitous storage networks.
Metzler is vice president of Ashton, Metzler and Associates. He can be reached at jim@ashtonmetzler.com.
One of the key survey results is that SAN use is steadily increasing. The majority of companies surveyed have deployed at least one SAN, and roughly a quarter have deployed five or more. Also, while the first wave of SAN deployment was usually based on fabric switches, which had few ports and were not terribly robust, that situation is changing. Today, more than 40% of companies have a director-class switch, featuring 128 or more ports and a high-availability design.
Another key indicator of SAN acceptance is that companies that have already deployed SANs are planning to increase their usage significantly. Tom Harrold, systems architect at Information Resources, says that over the past few years his company has moved every device in its open systems environment that requires external storage onto a SAN. His company moved to a SAN environment to gain flexibility in assigning storage in response to rapidly changing business requirements.
Michael Boykins, director of technology infrastructure at Outback Steakhouse, adds that the only applications he runs on a SAN are database applications. However, he says over the next two or three years Outback will bring all its applications onto a SAN to enable the company to beef up its disaster-recovery capabilities.
Application brownouts
While SANs are continuing their march toward mass-market adoption, they still have a significant growing pain to overcome: application brownouts. The phrase refers to having one or more applications occasionally perform notably slower than usual and then self-correcting. Some indications of application brownouts include the help desk receiving calls that an application is taking longer than usual to run a report, or an administrator noticing that a backup is taking longer than usual.
Roughly 70% of companies that have deployed a SAN reported having an application brownout at least once a month, and almost half of the companies that were surveyed indicated they did not have a good handle on what caused the brownouts.
Boykins says that although current technologies don't let him prove it, issues in the storage network often lead to application brownouts.
Harrold agrees, noting there are no tools that give him the visibility he needs to trend SAN performance.
The source of the problem could be anywhere, including the SAN, WAN, server, database or application server. One customer interviewed for our survey suspected that the SAN was at least occasionally the problem. The thinking was that with many server ports trying to gain access to fewer storage ports, the SAN has some built-in bottlenecks.
The typical response when application brownouts occur is to add bandwidth.
Application brownouts have a significant effect on business, primarily through lost productivity within a business unit. However, more than a quarter of the survey respondents indicated that application brownouts also result in lost revenue. More than 30% said the effect of an application brownout was significant or very significant, with more than half of the respondents indicating that if their company's ERP application experienced a brownout, the impact would be significant or very significant.
Harrold adds that if his company's ERP application experiences a brownout it can lead to delayed deliveries to customers. In addition to engendering ill will, these late deliveries also can result in financial penalties.
In terms of buying criteria, the survey showed that the most important items were reliability, availability, serviceability and scalability. At the low end were storage vendor recommendations. Initial cost of a SAN scored somewhere in the middle of the pack.
Because cost is typically a relatively unimportant factor in the selection of an emerging technology, and a very important factor in the selection of a legacy technology, the study results indicate that storage networks have moved out of the innovator phase and into a more mainstream adoption phase.
Harrold says that based on his experience developing a SAN environment, interoperability is his most important decision criteria, followed by management issues such as being able to monitor the performance of inter-switch links (ISL) and switch ports.
One of the characteristics of a mature marketplace is that customers tend to have a preferred provider. That is not the case with SANs, where the current base of SAN users is not tethered to their existing storage network vendors. Furthermore, users are reducing their reliance on storage vendors to recommend their storage network infrastructures, indicating that they feel more knowledgeable about SANs. This indicates a more experienced and independent market.
Also, companies are beginning to run their business-critical applications over a SAN. More than three-quarters of the respondents indicated that their company's ERP and CRM applications are SAN-attached. The fact that companies are now running these applications over a SAN helps explain why reliability, availability and serviceability are the most important decision criteria.
Data center changes
One of the key drivers in the current wave of SAN deployment is the extent of change taking place in the data center. The majority of survey respondents indicated that their company had made at least moderate progress with consolidation projects such as data center consolidation, storage consolidation and server consolidation.
Changes in the data center are going to continue and will further fuel the deployment of SANs. The majority of companies that have already embarked on consolidation projects and expect to consolidate more in the next 12 months. Boykins and Harrold agree that the major change in their company's data centers has been server consolidation. According to Harrold, over the last three years his company has reduced the number of Unix servers by 30% and is now starting a similar activity focused on Windows-based servers.
SAN architectures also are changing. Stories on best practices in SAN design typically discuss the use of a "core-edge" design. While there is some indication that this design might become the industry norm, it is not yet widespread. Roughly 30% of the survey respondents indicated that they virtually always implement a core-edge design today, with almost 40% reporting that they will implement this architecture a year from now. The survey respondents also indicated that they do not tend to oversubscribe their ISLs, particularly in the case where a SAN is supporting a business-critical application such as ERP.
Harrold says that a couple of years ago his company had isolated SAN islands each built around a director-class switch. His company has since moved to a core-edge design, with director-class switches deployed at the edge and at the core.
Based on the findings of this study, SANs have clearly moved out of the early adopter phase. Storage networks are large and getting larger. They are supporting more key applications, and finding value in consolidated storage environments. Buyers are becoming more discriminating, implementing more sophisticated architectures and selecting storage network products based on their unique technology requirements.
However, there also are some unresolved issues surrounding SAN deployment, including the widespread occurrence of costly application brownouts and the lack of effective management tools. As SANs continue toward mass-market adoption, users and vendors should take a moment to think about the needs for next-generation, ubiquitous storage networks.
Metzler is vice president of Ashton, Metzler and Associates. He can be reached at jim@ashtonmetzler.com. 