Storage Virtualization

Before we leave the topic of drives and RAID arrays, it is worth pausing a moment to see where all this technology is leading us. As noted earlier, modern operating systems abstract the data stored on a disk from the actual physical disk by creating named entities called volumes. The intent is to provide a means for moving data around in the server as needed.

There are many reasons you might want to perform a data migration, moving a volume from one place to another. Here are a few of them:

• You have just built a speedy new array and want to get better performance.

• Your array is failing and you have to move the data.

• You need a copy of your volume to perform testing on.

• You want to bring a new, more powerful server online and move your data onto that server.

• You want to move your volume elsewhere to improve capacity utilization.

• You need to move the data to another location in order to perform disaster recovery.

There are many good reasons to move your data or to have the ability to do so. Storage virtualization is a technology that creates a pool of storage that can be managed and made available to network clients and other servers. Virtualization software makes it possible to move volumes around from place to place. SANs and virtualization are powerful tools that make servers even more powerful. Let's now turn to Chapter 12, which explores the topic of SANs for creating distributed storage managed by and stored on specialized servers.