10 Advantages of SAN vs. DAS Page 2
6. Long Distance Connectivity
SANs have the advantage over all other storage connectivity for distance at 10km (about 6 miles). Not that you'll necessarily use that distance capability, but it's there if you need it. Having the advantage of distance allows you to consolidate your storage into an isolated location dedicated to storage and separate from the systems it serves.
7. Increased Utilization
Rather than hundreds or thousands of partially utilized local disks wasting power and generating heat in your data center, you could have dozens of SAN disks have no wasted space on them. How so? Thin provisioning on the storage side (i.e., on the SAN) uses space more effectively than local storage does. As a system requires more storage, the SAN allocates it dynamically. Yes, this means that physical systems can enjoy thin provisioning just like your virtual ones do.
Despite the benefit of more fully utilized disks, as highlighted in advantage No. 7, you do not need to use local disks for the server operating system. It's possible to run diskless physical servers and boot directly to the SAN for your operating system, swap space (pagefile), and all applications. That's right, just like virtual machines.
9. Centralized Management
If you have SAN arrays from several different vendors because your data center has grown over the years, stress not, SAN vendors have created software management tools to manage your heterogeneous environment with ease. But, better than multiple vendor management capability, all of your SAN environments can be centrally managed from this single interface. This capability provides efficient and centralized storage management.
10. Disaster Recovery
The cost of a SAN is high. As you can see, there's no entry for SAN being a particularly frugal technology in this list. However, in the case of disaster recovery, a SAN can and does earn back its high price by providing a speedy recovery when the clock is ticking. A SAN is a reliable and fast data recovery solution. Server systems might go offline, but the SAN remains available.
Ken Hess is a freelance writer who writes on a variety of open source topics including Linux, databases, and virtualization. He is also the coauthor of Practical Virtualization Solutions, which was published in October 2009. You may reach him through his web site at http://www.kenhess.com.