Global namespace: The Future of File System Management, Part 2. (Storage Networking).

Introduction

IT administrators spend a great deal of time on file management tasks (adding users, adding file servers, rebalancing storage, setting up failover, etc.) and data movement tasks (replication, migration, consolidation, data distribution). These are tedious and time-consuming for administrators, disruptive to users, and expensive for companies.

Companies are looking for better ways to scale and manage their file systems. Global namespace provides the answer.

In "Global Namespace--The Future of File System Management, Part 1," we defined global namespace as a logical layer that sits between clients and file systems for purposes of aggregating multiple, heterogeneous file systems, and presenting file information to users and applications in a single, logical view. The benefits of a global namespace are clear and compelling:

* Users (and applications) are shielded from physical storage complexities.

* Administrators can add, move, rebalance, and reconfigure physical storage without affecting how users view and access it.

* Global namespace provides a platform for developing value-added functions such as data migration, server consolidation, and disaster recovery.

With a global namespace in place, the administrator can perform data management and data movement tasks in less time, without disrupting user access to files. When files are moved, links in the namespace are automatically updated, which reduces manual administration and ensures continuous client access to data.

In this article, we will discuss how a global namespace simplifies file management, how to create and deploy a namespace, and the solutions it enables in an enterprise environment.

The Problem: File (Data)

Management and File (Data)

Movement

Stephens Company has 600 marketing and engineering users who are accessing files across five file servers that are shared by the two departments located in Houston and New York City. Marketing users are accessing files via multiple drive letters that are mapped to two NetApp filers and a Windows server, and engineering users are accessing files on three servers and one filer.

There are several issues with Stephens Company's current file system environment:

* Users find it difficult to locate and access files via multiple drive letters (which are increasing).

* File server Houl_W2K_Server12 is at 90 percent capacity, while NY_NAS_Server2 is at 20 percent, which means that users are beginning to get errors as they try to save large graphic files to Server12.

* To migrate files and rebalance storage between Houl_W2K_Serverl2 tY_NAS_Server2, the administrator must disable user access to the files that are to be moved, move the files to the NY filer, reboot and bring both devices back online, revise all marketing and engineering user login scripts, and inform users that the files have a new location so that their PCs can be reconfigured to access them. This will require at least 12 hours of downtime and the manual reconfiguration of every desktop and application that accesses the files.

The Solution: Global Namespace

There is a simple, long-term solution to Stephens Company's data management and data movement issues. Deploying a global namespace will simplify data management and enable transparent data movement.

Figure 2 shows the new configuration, in which a global namespace has been inserted between users and physical storage. Users now access their files through shares called \\namespace\users\marketing and \\namespace\users\engineering. This was a non-disruptive installation, as the namespace was installed on top of the existing infrastructure. Users continue to access files in the same manner as before, with no retraining needed.

Note how the file system environment is changed by the introduction of a global namespace:

* All users see a single, logical view of files through the namespace.

* Users access all their files through a single drive letter--which will not grow, and allows them to continue accessing files in a familiar way.

* Data can be organized and presented to users in a way that makes sense to them, irrespective of how or where the data is stored.

* Data management and data movement are performed "behind the veil" of the namespace.

* Data changes are automatically updated in the namespace, and require no client reconfiguration.

* Administrators can expand, move, rebalance, and reconfigure storage without affecting how users view and access it.

* Data management and data movement require far less physical administration and are performed in less time than before.

Having a global namespace in place makes it easy for IT managers to accommodate the changing needs of an organization while also reducing storage costs.

How It Works

Global namespace does for files what DNS does for networking--it provides a directory service. The global namespace resides on a namespace server, which can be any Windows 2000 or Windows 2003 server within the namespace configuration. Clients (users and applications) view and access files through the namespace.

When users select a file from the namespace, a request is sent from the client machine to the namespace server. The namespace server receives the request, provides file location information back to the client machine, and redirects the client to the file in its physical location. The whole process occurs in an instant, and is transparent to clients.

This architecture provides several significant advantages over other file system aggregation approaches:

* There is nothing in the path between clients and the data, which is important for two reasons: performance is not impeded, and there is no single point of failure.

* The namespace server may be clustered to provide high availability of the namespace.

* There is no client installation, which simplifies namespace deployment and management.

* It takes only minutes to install the namespace software, and less than an hour to create and populate the namespace--an administrator can deploy a namespace and begin receiving namespace benefits in a single day.

* Physical desktop and server management is significantly reduced, as data movement and management are simplified and no client reconfiguration is required--ever.

Creating and Deploying a Namespace

There are several requirements that are key to the effective use of a namespace. Two global namespace solutions available today that meet these requirements are NuView[R] StorageX[R] and Network Appliance[R] VFM[TM]. Both are sophisticated software products that enable creation and management of global namespaces of any size (see Table 1).

Using Global Namespace in the Enterprise

Once implemented, a global namespace can dramatically simplify and reduce the costs associated with storage tasks, such as server consolidation, storage expansion, and disaster recovery.

Simplified Storage Consolidation

As mentioned earlier, many organizations today are taking steps to reduce the cost of storage management, as well as storage acquisition, including the following:

* Reduce the number of servers/storage devices

* Increase the capacity utilization of existing storage

* Migrate and load-balance data between storage devices

Let's look at the administrative processes required to perform server consolidation with and without a namespace in place (see Table 2).

Non-Disruptive Storage Expansion

Just as global namespace makes it easy to consolidate storage, having a global namespace in place also simplifies storage expansion. Global namespace can facilitate rapid SAN integration, simplify file server expansion, and enable NAS scaling.

Transparent Disaster Recovery

Global namespace enables rapid disaster recovery all the way to the user. Let's look at a scenario:

Stephens Company has its primary operations in New York City. The NYC data center stores information that is accessed by 10,000+ Stephens users. A disaster strikes, causing the primary filer in the NYC data center to go offline. To restore user access to data, Stephens administrators must take users offline while they rename and reboot replicated servers, re-route the network, and then reconfigure client machines to access them. It takes more than 24 hours to restore user access to the data.

Let's replay the scenario with a global namespace solution in place (see Fig. 4):

* A user regularly requests a file that is stored on a server in the NYC data center.

* Today, the NYC server is unavailable.

* Because the user is accessing files through the namespace, he is transparently redirected to the backup filer in New Jersey, and is able to access the file, as if nothing had changed.

Global namespace is the only way to enable immediate, transparent client failover to a backup file server in a different location. When the site failure occurs, client calls to the failed servers are transparently redirected to the replicated servers in New Jersey. No client reconfiguration or network rerouting is required. The time between failure and restored client access to files is minutes, not hours or days.

The benefits of using global namespace to prepare for disaster recovery are significant:

* Disaster recovery is rapid and transparent.

* Little or no user downtime.

* No storage reconfiguration is required to restore client access to data.

* Policy-based failover can be set up and executed without manual intervention.

Conclusion

By now it should be clear that global namespace delivers immediate, significant benefits to companies who are dealing with data management, data movement, and data availability issues.

"By creating a universal namespace, users are never disrupted and administrators can change, add, grow, or shrink without ever affecting the environment."

Steve Duplessie, Enterprise Storage Group

Table 1

Requirements                     How StorageX and VFM Meet
                                 the Requirements

* Tools for namespace            * Discover shares and automatically
  creation and population          construct a name-space that the
                                   administrator can modify as needed

* Ability to synchronize         * The namespace is automatically
  the namespace with the           updated when storage is added, moved,
  underlying physical storage      changed, or reconfigured

* Namespace monitoring and       * Provide distributed file system
  management                       and namespace monitoring and
                                   management from a single console

* High availability of the       * The namespace can be clustered for
  namespace                        high availability and to eliminate
                                   any single points of failure

* Easy to change or reconfigure  * Both products provide simple
  the namespace when needed        processes for non-disruptive
                                   namespace reconfiguration

Table 2

Traditional Server/                     Global Namespace-Enabled
Storage Consolidation                   Consolidation

* Plan downtime and inform              * Migrate data to new location
  users                                 * Decommission old servers
* Migrate files                           and storage
* Edit login scripts                    * Total administrative
* Edit backup tasks                       time: 3-5 hours
* Inform users of new locations
  and file shares
* Have all users re-login
* Field user calls for broken
  mapped drives and shortcuts
* Field user calls for broken
  applications
* Locate and correct all dependent
  applications
* Decommission old servers and storage
* Total administrative time: 3-5 days

www.nuview.com

Rahul Mehta is the CEO of NuView, Inc. (Houston, Texas)