Senior Technology Editor
Published: 01 Aug 2011
Virtualization often makes storage provisioning easier, adds value to storage, and eases the traditional pain of managing or allocating storage resources among various applications and users.
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But virtualization doesn't guarantee trouble-free storage provisioning or improved storage performance. Administrators must allocate the right amount of virtualization storage -- at the right performance level -- for each application. It's also important for virtualization storage capacity and performance to remain within acceptable parameters as business conditions change.
We’ll explore some of the nuisances of virtualization storage, such as challenges related to storage provisioning, storage performance and remote storage methods.
Solid storage provisioning tactics
The fundamental goal of storage provisioning is to make storage resources available to corporate applications. Storage virtualization does not alter this, but the abstraction that virtualization introduces can mask some underlying problems down the road.
One of the biggest issues to contend with surrounding storage provisioning is the storage abstraction itself. Virtualization effectively gathers storage resources into a single pool that can then be carved up and allocated to applications. That's a great approach if all virtualization storage is the same, but an enterprise can include a wide range of disks and systems that have varying levels of performance, protection and reliability.
To ease storage provisioning, make the effort to group similar virtualization storage resources together. Since storage systems can vary dramatically in levels of intelligence and automation, at least use built-in management tools to verify that storage has been pooled adequately. For example, use the tools to make administrative choices that prevent you from making storage provisioning mistakes and pooling greatly dissimilar storage types.
"You're probably OK to stitch those EMC Symmetrix RAID 5 storage pools in one logical [virtual] pool and then provision LUNs [logical unit numbers] out of that pool," said Ray Lucchesi, president and founder of Silverton Consulting Inc., a storage and systems consulting firm in Broomfield, Colo.
Lucchesi says grouping similar storage resources also applies to disk storage performance, and he advises administrators to keep 15k RPM and 10k RPM drives separate. "Do as much as you can to match those characteristics across all the storage in a storage virtualization pool," he said.
Shifting storage provisioning responsibilities
In the short term, many storage vendors now offer plug-ins to the virtualization management layer that make creating a new LUN or volume much easier than with standard virtualization storage management tools. This represents a shift of responsibility from the storage team to the virtualization team, in an effort to improve storage performance.
In small shops, where each team is a single person or a small group, political battles around implementing these virtualization storage plug-ins are rare. In large enterprise environments, however, it's unlikely that the storage team would want to devolve this storage provisioning responsibility to virtualization administrators.
Of course, businesses may eventually move to a self-provisioned virtualization storage model, in which creators of new virtual machines (VMs) consume storage in a different way. These cloud consumers will be further from the day-to-day carving up of resources from the storage array. That doesn't mean that responsibility for configuring virtualization storage correctly and presenting it to the "cloud layer" just evaporates. In fact, storage administrators will need to carefully present storage so that end users are aware of storage performance, resiliency and costs incurred.