SANs enable Internet-related businesses

Posted on February 02, 2000

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Potential advantages include better backup and replication, centralized management, scalability, and sharing of resources, files, and data.

By Greg P. Schulz

The Internet has changed the way business is conducted. Information must be available 7x24x365, from anywhere in the world. New business models (e.g., "virtual stores") have emerged, forcing changes in technology infrastructures to support dynamic business requirements.

With the rapid and continued growth of the Internet has emerged a new category of business: sometimes referred to as Internet-Related Business (IRB). IRBs include Internet Service Providers (ISPs), Application Service Providers (ASPs), e-commerce companies, and others.

The common services needed by IRBs include networking, processing, management, and information storage. A storage area network (SAN) enables these services via storage resource sharing, file and data sharing, backup, replication, management, and scalability.


In a SAN or storage utility model, servers and storage resources plug into service access connection points.
Click here to enlarge image

SANs enable IRBs to remove or abstract physical storage and information from specific host systems. This flexibility enables companies to meet the changing and dynamic needs of the IRB environment, including acquisitions, mergers, expansion, and new services.

Storage management for IRBs

Networking technology is the basis of the infrastructure we now call the Internet or World Wide Web. Now, a similar transformation is occurring on the "other" (e.g., storage) side of servers. Several technologies exist to enable concepts such as "storage utilities" to be implemented in an open, cost-effective manner.

Storage area network is the generic term used to describe the combination of these technologies, including Fibre Channel. SANs and associated technology enable the storage utility model to be implemented.

For IRBs and other organizations, the potential benefits of SANs and storage utilities include:

  • Increased ability to share information resources and data.
  • Reduced duplication (hardware, service agreements, staffing).
  • Centralized management of distributed environments.
  • Reduced complexity (interfaces, devices, management, backup).
  • Flexibility to adapt and implement new business objectives.
  • Increased investment protection and asset utilization.
  • Increased distance between servers and storage devices.
  • Simplified backup and recovery for data protection.

SANs and storage utilities are conceptually similar to utilities such as phone and electric services providers. Rather than having one physical server with duplicated resources (disk, tape, backup, and management), each device plugs into a service access connection point (see figure above). From these connection points, the systems supporting various applications or IRB functions can access and use the storage or data services they need.


SANs enable replication, remote mirroring, centralized backup, and data sharing between various server platforms.
Click here to enlarge image

The storage utility, SAN, or data services model empowers IRBs to solve specific business issues. Consider an environment with two sites, one on the West Coast and the other on the East Coast (see figure). In this example, different aspects of IRB storage management can be addressed, including replication or remote mirroring, backup, and data sharing for Web, email, database, and news servers.

Critical data is replicated or remotely mirrored between the two locations, and perhaps others, for high availability and workload balancing. To help reduce management, replication and data migration are used to reduce the backup window, maintain data availability, and speed Web data migration.

Some common storage or data services required for IRBs include block, file, connection, backup, replication, management, and support services.

  • Block services. The basic building block for a SAN or data services model is block storage, provided by RAID arrays. A block service device provides high availability via fully redundant components to provide high performance and fault isolation. Block service devices should be scalable, modular, and flexible to meet the changing needs of IRBs' dynamic application requirements. Storage allocation, security, and setup should be flexible and under user control. To exist in an open environment, block devices should be host independent, without requiring special host software or drivers.
  • File services. File services provide file and data sharing using underlying block services to serve data and files to Web hosts and clients. Data and files are accessed via standard network interfaces (e.g., Ethernet, FDDI, ATM) using protocols such as NFS and CIFS/SMB. In the past, file services have been possible by attaching dedicated storage directly to host systems and serving it to clients or by dedicating storage to a file-server appliance. In the storage utility, SAN, or data services model, block storage is available for use by hosts, as well as for file services without being dedicated to any one platform.
  • Connection services. Connection services provide the infrastructure and include Fibre Channel switches, hubs, host bus adapters, cabling, diagnostics, network interfaces, and management capabilities. The connection services should be interoperable, scalable, and modular to adapt to the dynamic needs of IRBs.
  • Backup and recovery services. Whet-her restoring an accidentally deleted home page, restoring a journal file to resolve a billing or security issue, or receiving lost data, backup and recovery services complement high-availability block services.
    Backup services can be used to migrate backups off LANs to shared tape libraries for LAN-free backup, which can evolve to server-less backup. Backup services should provide on-demand backup and restore, the ability to back up open files and databases without having to take applications off-line, and the ability to perform remote backup and recovery.
  • Replication services. Block services with RAID protection, combined with backup/recovery and replication of data to other locations, not only provide the highest levels of data protection and accessibility for IRBs, but also management and configuration flexibility. Replication or remote mirroring can be used for data movement between data centers during application rollouts, turnovers, consolidations, and for load balancing. In addition, replication services and remote/local mirroring can help reduce backup windows for IRBs by keeping data available and providing multi-site protection of critical data.

    IRBs provide data and information on a 7x24x365 basis. Flexible services to meet the dynamic needs of IRBs are needed to provide storage and access for critical data when and where it is needed. Implementing the storage utility model with SAN technology, information can now be stored where it is needed without having to have it physically connected to specific servers.

    Greg P. Schulz is a senior technologist at MTI Technology Corp. (www.mti.com), in Anaheim, CA.


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