Server virtualisation is a great way for your IT organisation to battle today’s economic challenges. You can reduce costs through server consolidation, which in turn increases ROI as you run multiple workloads on a single server. Plus, the ability to deploy new applications - and scale them up or down - boosts business agility.

But watch out for pitfalls that can undermine these advantages. As companies large and small have learnt the hard way, you can negate the cost-saving benefits of server virtualisation by choosing an inefficient SAN storage solution that does not properly support the advanced requirements of virtualised environments.

While you ride out this recession, you need to make the most of your virtualisation investments. It literally pays to be aware of the right storage choices. Here are some things to keep in mind:

• External shared storage can be very inefficient. For example, a volume allocated to hold 100 GB of data may only be required to hold 50 GB, and that remaining capacity may not be used for years. This problem becomes more evident when temporary volumes supporting test and development environments still consume 100 GB (although the volumes will never be filled and will only be needed for days or, at most, weeks during testing). Such inefficiency means more upfront storage purchases and suddenly escalating costs.
• More virtual machines equate to more logical volumes, and more snapshots for backups. Traditional SANs require a 100 percent reserve, so the same half-full 100 GB volume now requires an additional 100 GB for each snapshot. Again, more costs and more wasted space./li>
• More often than not, implementing high availability across sites requires an additional storage system, as well as synchronous replication software to enable continuous data availability in the event of a single SAN failure. This results in more complexity and increased storage expenses.
• Disaster recovery using remote replication boosts storage costs yet again. In fact, storage replication solutions often require multiple copies of data and massive capacity reservation that can increase storage inefficiency by a factor of three. First, a snapshot must be created on the local system, requiring a 100 percent reserve. Then the remote copy requires a 100 percent reserve on the remote system. Finally, a copy must be created before a server at the remote location can mount and use it. It all adds up.

The deployment model for traditional SANs is to purchase a storage system with the capability for future expansion. But with IT budgets being curtailed today, how can you budget for future requirements and expansion?

If you are a small or medium-sized business, you face more cost deterrents. Even in good times, your budget dictates the purchase of a lower-cost SAN solution, which in turn often lacks the features required to support your high availability and disaster recovery requirements, not to mention desired enterprise-class management features. Of course, you can add on software, but that’s an expensive option as well.

An attractive alternative to traditional SANs, iSCSI SAN solutions offer you storage for virtualised environments that hits all the potential pain points around cost and management. Go one step further, to iSCSI SANs with a scale-out architecture, like the HP LeftHand P4000 SAN, and you gain additional advantages in terms of scalability, high availability, disaster recovery and performance.

Storage clustering creates a scalable storage pool by aggregating the critical components of a number of storage systems into a single pool of resources. This pool accepts and responds to iSCSI requests as a single system, as all physical capacity is aggregated and available to the volumes created on the SAN. Need more storage capacity and performance? Simply and seamlessly add additional storage nodes to the pool - without downtime.

By providing built-in thin provisioning, HP LeftHand P4000 SAN solutions dramatically improve overall storage efficiency. Thin provisioning allocates space only as data is actually written to a volume. You can purchase only the storage you need now, and then add to your storage pool later as your storage requirements increase. This increases storage utilisation and ROI while helping you defer capital expenditures, which is always a smart move in these budget-tight times.

What’s more, HP LeftHand P4000 SAN solutions include built-in support for your high availability and disaster recovery implementations, thus eliminating the need to buy add-on software. You also get superior, scalable performance plus straightforward management that any server administrator can understand and put into practice right away.

Without a doubt, virtualisation opens up a new range of possibilities for your data centre: Improved server utilisation with high availability and disaster recovery. Performance management through dynamic workload balancing. Simplified management with all servers harnessed as a single, uniform pool of resources.

Don’t lose what you gain with server virtualisation to inefficient storage. Make sure you choose SAN solutions that fully support your virtualised environment. That way, you can have all the benefits of server virtualisation and:

• SAN storage that drives down costs by increasing storage utilisation
• Flexibility to purchase storage as you need it, making it easier to work within today’s budget constraints
• Increased capacity and performance as you add to your storage pool, avoiding traditional SAN bottlenecks
• Peace of mind that comes from knowing you can continue to operate continuously in the event of a local or geographic failure
• Ease of management so that server and storage administrators alike can manage your iSCSI SAN

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