Storage virtualization is getting a lot of press these days, but it isn't new. Host-based volume managers have long enabled nondisruptive extension, reduction and migration of application data independent of the disk storage. Soon after the emergence of host-based volume managers, storage left the host, and we connected to external cached disk arrays, which hid the messy details of SCSI targets, controllers and RAID protection from the servers. Not long after that, we installed storage area networks (SANs), further virtualizing the connectivity to storage. No, virtualization is not new; it's what modern storage systems are all about!
Even with all the storage virtualization benefits we enjoy today, there are still several storage management problems left unsolved. Storage customers complain that it's tough to migrate data from one
storage platform to the next and that the administrative burden of storage systems is still too manual and difficult. These challenges mean that storage teams have to spend all day keeping the system running, instead of optimizing it.
SAN-based storage virtualization holds the promise of addressing these problems, enabling you to improve your customer's data management and deliver storage efficiencies. Empowering customers to migrate and manage data quickly means that they will be more inclined to refresh aging technology. This tip covers five value propositions for SAN virtualization.
- Single point of administration: Customers understand that a little friendly competition between storage vendors can help reduce the price of storage; SAN virtualization can be implemented in multi-vendor storage environments, so if a potential customer doesn't run the brand of storage equipment that you offer, converting them to a SAN virtualization setup could open the door to storage hardware sales. SAN-based storage virtualization provides this benefit by virtue of the fact that all of the SAN storage is provisioned to the virtualization device, so from that point on, all of the storage administration occurs at the virtualization layer.
- Nondisruptive data migration: Many customers do not replace their storage arrays when the lease or support expires or when the products are fully depreciated -- not because it is cheaper to keep the storage (the manufacturers make sure it's not), but because it is very difficult to migrate to the next storage platform. Without storage virtualization, migrations often require application outages and lots of sweat equity. These efforts are extremely difficult to coordinate across the various teams and business units involved. With SAN virtualization, the storage team can execute disk array swap-outs without impacting anyone else. This capability brings benefits to storage managers and VARs alike; migrations suddenly become not only possible but easy enough to make them worthwhile, allowing storage managers to take advantage of the declining cost of storage and bringing VARs an opportunity to sell new storage.
- Information lifecycle management (ILM): Customers want to know that they are putting their application data on the most appropriate tier of storage. Data access patterns are a key criterion in determining where to put the data. Often, a single business application or database has certain regions of data that are frequently accessed and require high-performance storage, while other regions are rarely accessed and could exist on more cost-effective storage. Because SAN virtualization tools sit between the server and the storage hardware, they have awareness of the access patterns. If the virtualization engine can use this access pattern information and leverage its online migration features, it may be possible to transparently relocate frequently accessed data to more expensive, high-performance storage and move less frequently accessed data to less expensive storage, bringing true ILM within reach.
- Improved allocation efficiencies Storage managers know that improving asset utilization is a quick way to lower the total cost of ownership (TCO) for their department. One of the common causes of low utilization is that the application teams demand more storage than they need. This may be because the process for requesting more storage is too slow; on the other hand, it could be because the application is new and there's not enough history to properly plan for growth. Storage virtualization promises to solve both problems. In the first case, the pace of deployment can be improved when all storage, regardless of brand or type, has a single administrative interface for allocation. And capacity planning challenges could be alleviated with thin provisioning services in the virtualization layer, which allow pre-allocation of storage and shared free space across applications optimizing unused disk, which is the most expensive storage asset.
- Heterogeneous replication One of the huge challenges associated with maintaining agnosticism among disk array vendors is disaster recovery replication. Most array-based storage replication is not heterogeneous, meaning that the production and disaster recovery frames must be of the same brand and often of the same type. Host-based replication options are heterogeneous, but management is cumbersome when a large number of hosts have replicated data. SAN virtualization can split the difference, providing a single method of replication for multiple types of storage arrays and a limited number of management points.
Storage virtualization in all of its forms has been providing benefits to businesses for years; yet there are still some challenges that remain. It's easy to see that SAN-based virtualization holds a lot of promise for the industry. Discuss these value propositions with your customers to open their minds to the possibilities of SAN virtualization.