perspective The initial interest in virtualization was on pure-play server consolidation and its corresponding savings on capital expenditure and management. Now, organizations are looking to take virtualization to the next level--that of enhancing availability.
Application availability and the business continuity that results from this, can now be improved since virtual machines (VMs) can quickly be brought online on other hardware in the event of a failure. This provides a much quicker alternative to building a new physical server. It is also significantly less costly in terms of time and money than complex application-specific clustering offerings.
Availability is additionally improved as hardware maintenance can be performed non-disruptively when moving a live VM to another server. As such, virtualization helps IT deliver better service levels to the business. Tools with advanced functionality simplify disaster recovery and improve reliability by fully orchestrating and automating the recovery of systems after a disaster.
There is also an increasing realization that virtualization can impact the desktop computing infrastructure (not just servers) by simplifying the rollout and patching of thousands of desktops. It allows centralized management of an organization's desktops from within the data center where IT has advanced technologies and strong process control that usually do not exist outside the center. Besides efficiency, there are huge positive security implications to this centralized model.
Storage virtualization for businesses
In its purest form, virtualization lets users add storage capacity using inexpensive, commodity disk and tape drives to dynamically manage those storage resources as virtual storage pools, with little regard for what physically resides on the backend. Intelligent storage services have historically been implemented within storage systems or in host-based software running on servers.
Today's enterprise-class infrastructures typically include multi-vendor server environments, diverse connectivity technologies, and multi-vendor tiered storage environments. Organizations require the ability to allocate any storage to any application based on the needs of the business, and to do so non-disruptively. Networked storage virtualization enables organizations to deliver the right information at the right performance level and the right functionality to the business at the lowest total cost.
Virtualization also promises to enhance overall platform independence, along with system flexibility and utilization. Maximizing system flexibility and utilization are critical to ensuring the storage investment is delivering the tangible benefits and dividends expected. Virtualization is not simply a fancy way of viewing and interacting with data, but can tangibly improve the performance of enterprise storage and the value of business information.
In addition, virtualization breaks the dependency on the underlying hardware. It creates a virtual layer over the servers/storage from multiple vendors and creates a pool where various applications can be dynamically provisioned as required by the customer.
In essence, virtualization enables the creation of logical (virtual) representations of physical IT resources such as memory, networks, servers and storage--that perform as if they were actual resources. In virtualized storage environments, these logical components can interact with their physical counterparts including SANs (storage area networks), disk arrays, tape components and other storage media.
The combination of server and storage virtualization provides an unmatched IT infrastructure foundation in terms of flexibility and agility, which enables an IT department to:
- Easily deal with changes in the business environment;
- Redeploy equipment;
- Spend in small increments as business conditions warrant, instead of big up-front investments and overcapacity;
- Deliver meaningfully differentiated QoS (quality of service) levels at meaningfully differentiated costs;
- Transition to newer technologies in storage and servers without disruption to users; and
- Appropriately match resources to the criticality of the business application.
Storage virtualization has multiple advantages but it may not be the only, or the best solution to a specific problem faced by an enterprise. Enterprises need to be aware that many challenges can be addressed by a broad range of technologies from various vendors. Here are the broader issues to be considered:
- Compatibility: There is a potential for finger-pointing between vendors when interoperability errors occur between the virtualization product and the storage systems being pooled. In the meantime your systems are down or data is corrupted. The highest standards of interoperability testing should be demanded before considering an implementation.
- Scalability: Storage virtualization's value comes from its ability to scale--maximum value is achieved when the whole target environment can be aggregated into a single logical view or "virtual pool". Enterprises must make sure the virtualization products can do this without getting in the way.
- Functionality: Enterprises should use their existing investments in processes, skills, training and people who use these tools. Aside from cost, the "replacement" functionality must be benchmarked against the existing technologies.
- Management: Virtualization devices disrupt existing storage-resource management. If you have an environment with an end-to-end view of management, any virtualization device will have to be re-integrated into it.
Diagnosing problems can be hard and information from storage arrays, hosts and virtualization systems must be combined, monitored and correlated to allow proper identification and remediation. The reintegration of the management view is essential to achieve the manageability benefits of a virtualized environment. - Support: Virtualization devices add another layer of complexity--the virtualization vendor must take responsibility to ensure interoperability with everything behind the device.
If you are not already leveraging some form of virtualization, the following questions will help you better sort out the various options:
- Keep in mind the issues or challenges you aim to address with virtualization. For example, are you looking at volume, LUN (logical unit number) or file system pooling and aggregation to improve capacity utilization, enhance interoperability, reduce management complexity, reduce costs or eliminate real or perceived vendor lock-in?
- Ask yourself if you need or simply want virtualization. For example, you may want virtualization to create a seamless transparent pool of unified storage to reduce costs and eliminate vendor lock-in. Alternatively, you may need virtualization to enable transparent data migration and movement for tiered storage or to eliminate downtime caused by technology upgrades or disruptions from capacity movement and allocation.
- How will virtualization fit into your existing environment? Look at what procedural and configuration changes will be needed, along with training and education requirements. What other technologies will be required on host servers, including applications, agents, managers, drivers or other forms of software?
- Does the storage virtualization product let you use the sophisticated capabilities of the pooled storage arrays for areas such as cloning/snapshots/replication, or does it disable or replace them? Will it scale in terms of number of storage devices and servers attached, overall capacity, performance capabilities, ease of use and availability?
The costs of a storage virtualization vary according to the amount of information that needs to be virtualized. For example, a typical EMC Invista system with 10TB of storage would cost around US$100,000. As for return on investment, a survey of 210 IT managers by Enterprise Strategy Group revealed early adopters of storage virtualization achieved average cost reductions of 24 percent in hardware, 16 percent in software and 19 percent in SAN administration. Of the respondents, 96 percent expressed an interest in implementing storage virtualization in the next 24 months.
Two optimization tips
First, run a server virtualization assessment to identify under-utilized resources and determine which workloads are candidates for virtualization and consolidation. This will give you valuable input for building a virtualization business case.
Next, do a data classification assessment to identify areas for cost savings through storage tiering, help get capacity planning under control, streamline backups and define data management policies.
Virtualization can have great benefits for almost any IT organization regardless of size. Start simple and evolve, understand your scaling issues, and keep in mind what the specific virtualization technology is designed and intended to support. Realizing different products are aimed at various functions, and then aligning those capabilities to your needs, can be the key to a successful storage virtualization deployment.
Chris Insinger is the VMware business director at EMC Asia-Pacific and Japan.