Reducing time to provision and time to manage while reducing storage footprint.

Virtualization of servers, storage, backup and their very infrastructure are being integrated into Data Centers at a rapid pace. It is the only sane response to the ever-increasing demands being placed on IT by the organizations that it supports. Virtualization of storage is becoming a key requirement being placed on manufacturers by IT End-Users. As more virtualized systems become implemented and the user community is ready for more, the logical next step is Virtual Domains.

An advanced virtualized storage system can employ Virtual Domains in the same way a server can employ server virtualization solutions to host multiple, independent OS's which are protected from one another.  A Master Storage Administrator assigns a virtual “slice” of storage (a “virtual array”) to a community (a department, line of business or application group) within the organization. For example, this could be an IT Manager for a particular line of business or even just a sub-group within the IT Infrastructure. Once the users of this domain are assigned, they can manage and provision the storage among their group without causing concerns, in fact without visibility, to the other groups within the organization. This capability can dramatically reduce the time required to provision storage by moving the decision of storage provisioning closer to the front lines.

Virtual Domains also reduce the workload of Storage Administrators. In the past, there has been a reluctance to allow a more granular and departmental approach to the management of storage resources. The traditional causes for this reluctance were the lack of tools to properly delegate authority and concern about that lack of control. Virtual Domains resolve both of these issues; it provides the tools for a more granular or departmental management of the storage resources, while at the same time ensuring that the storage administrators are able to keep a watchful eye on the broader storage assets. 

It also reduces the workload of the central IT staff.  The ability to let the Exchange Administrators, for example, provision, allocate, and basically manage their own storage area would be a great advance in IT responsiveness and end-user productivity. It also would allow for an optimal use of the total storage assets allowing for significantly improved cost amortization of the storage investment.

This is an entirely new capability that has been previously unavailable to the storage professional. In the past, the only way you could provide shared management of your shared storage array was to essentially grant access to the entire system. Certainly a Storage Administrator could create and assign a LUN (Logical Unit Number) to a server and allow the group administrator mange the volume. The problem is that the server administrator could only partition that storage on that particular server. If the group administrator had excess capacity on some servers in their group that they wanted to re-assign or he simply wanted to add storage to a server, it would require the group administrator to submit a change order to the storage administrator and wait for that change order to be processed.

The lack of Virtual Domains requires that departmental management of storage is done on a server-by-server basis. The Exchange team, for example, can not manage their storage resources as a whole, provisioning and reallocating storage across servers as needed. This is especially frustrating if within that group they have available storage on one server that they know they could reassign to a more critical process. Since most application groups within an enterprise have multiple servers, each requiring their own storage, having to manage the storage on a server-by-server basis as opposed to an application group or departmental level is highly ineffective. In order to change the storage assigned to those servers,  the Storage Administrator would need to grant each department full access to the storage system or the storage administrator has to make all the changes, which is today’s reality without Virtual Domains. As a result the storage administrators are now buried with change requests for each individual server task.

To get around the difficulty with provisioning and reallocating storage, departments or application groups tend to over-request storage resources. This results in broad, organization-wide storage inefficiency with under utilization being the norm as opposed to the exception. All this under-utilized storage has to be purchased, managed, powered and cooled resulting in considerable wasted expense to the organization. 

In an environment with Virtual Domains, the Storage Administrator could provision storage for the department or application group as a whole. When the need arises to provision more storage or reallocate that storage it could be done by the department without notifying the Storage Administrators, essentially creating a self-service model for storage. With Virtual Domains provisioning and reallocation, response times evaporate and the need to over request storage assets is no longer needed; dramatically reducing storage acquisition costs, storage administration time as well as power and cooling requirements.

Storage Virtualization Required

True Storage Virtualization is a required foundation for Virtual Domains. True Storage Virtualization leverages most, if not all, of the available disks in a system and sub-divides those disks creating virtual volumes with the appropriate level of RAID protection across a maximum number of disks. This capability greatly simplifies the provisioning of storage and also enables the thin provisioning of storage. 

Thin provisioning allows you to allocate storage before it is actually used or even purchased, but you only actually consume that storage as the application writes to it. You are leveraging the probability that the actual consumers of that storage will never use all the capacity they thought they would or they will consume that storage so slowly and at a pace slower than your ability to backfill, so you will be able to backfill capacity prior to user needing it.

See our earlier article Thin Provisioning Basics for more details.

The Virtual Domain should leverage the rest of the Virtual Storage functionality at a domain view level. The ability to replicate data from one storage system to another is a standard requirement. Virtual Domains should integrate into that capability, so that the Virtual Domain environment is replicated to the secondary site intact for secured access even in the case of a disaster. Also the individual domain owners or the storage administrator should be able to control which component of each domain is replicated.

Virtual Domains also provide a unique view of reported storage information. The Virtualized systems reporting tools should be able to provide granular reporting on a domain level for the domain managers and system wide reporting for the storage administrators. This would allow the Exchange Storage Administrator to see the historical performance and capacity utilization for that particular environment while the Storage Administrator could see a holistic view.

The Non-Virtualized Response

Some manufacturers have tried to work around their lack of virtualization foresight by developing “bolt-on” technologies that solve these specific capability requests of end users. For example, to address the requirement for virtualization there has been an attempt to partition, sub-divide or create domains within advanced storage arrays. These partitions are hard, not virtual. They typically have a finite number of disks and storage processors assigned to each partition. In most cases, the disks and storage processes being assigned to one of these hard domains is fixed, therefore greatly limiting the Data Center’s ability to respond to requests from the business.

Virtual Domains on the other hand leverage all the available disk and storage processors contained in the system, leveraging the performance and scalability of the storage array across all domains.

How it Works

Leveraging the inherent simplicity of creation, management and provisioning of virtual storage systems, Virtual Domains are as easy to use as they are secure. A Master Domain Administrator creates or adds sub-administrators from an existing LDAP directory infrastructure. The Master Domain Administrator then will create a domain, which is typically capacity based. The capacity of the Virtual Domain can be virtual (thin provisioned) as well. The last step is for the Virtual Domain to be assigned to a user or group. From that point the sub-administrator can perform all the typical storage management tasks that would in the past have required the involvement of the primary Storage Administrator.

Security

Virtual Domains are secure. Once the sub-administrator has been assigned to the Virtual Domain they can only interact with that domain. They can’t create, alter or even see the other storage that is assigned to other domains in the system. This can reduce unnecessary storage foot-print caused by organizational walls.

Political issues within the business often cause these organizational walls, but they could also be caused by the real world requirements of compliance or business unit differences. Whatever the case, there is rarely a Data Center that does not have multiple separate storage arrays and even SANs specifically to address those walls. This results in islands of SANs that are merely recreated on larger systems, worsening the problem that they were originally intended to address (i.e.,  under provisioned storage and under utilized storage processors).

Cost Savings

When used to address this very real issue within a Data Center, Virtual Domains will save the organization real budget dollars by leveraging the storage processing power and capacity across all the business units. This results in access to greater performance and capacity for the entire organization. This capability will also create a real impact on reducing power requirements. Storage processors sitting idle but turned on, or a series of disk arrays sitting idle but powered on, strain the power and cooling resources within the data center. By reducing the physical number of storage processors and spindles required you in turn reduce your Data Center’s appetite for power.

Virtual Domains, A Requirement for Enterprise Virtualized Systems

In the Enterprise, Virtual Domains have to be considered a requirement. The value in a Virtualized Storage Array is leveraging all of its spindles across all of its available storage processors. If you don’t have the ability to adhere to organizational walls, you will end up buying multiple virtualized systems that can’t share between each other, thereby mitigating virtualization’s primary benefit. With Virtual Domains in place, you can truly build a single storage center that is virtualized across the Enterprise while adhering to the vertical reality of your business.