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datacenter as well as humidification, UPS support, power distribution, and so on. Over that
same time span, a 7200 rpm 1TB drive with a RAID 5 configuration would produce a bit
more than 2 tons of CO .
2
Again, this is just the case for one drive. If your organization replaces hundreds or
thousands of similar drives, you can see the level of impact realized.
NOTE Typically, 80 percent of user data is inactive and best suited for storage on a SATA drive.
Real Estate Using fewer disks also helps reduce real estate costs. By using 21 spindles
instead of 274, a company can reduce its total storage footprint by 92 percent. Not only do
you have the potential to lease less space, you also have the opportunity for future growth.
Space-Efficient Snapshots
Data protection brings its own set of headaches to the SAN. Datacenters that use RAID
storage experience higher costs as capacity is added because RAID overhead increases.
Storage preallocated for specific applications is inefficient, because a lot of expense comes
from unused space. To protect data, data snapshots guard again loss or corruption, but full-
volume snapshots add even more expense.
Space-efficient snapshots do not require full-volume clones for creation or recovery.
This allows for more snapshots to be maintained on your system. This allows you to restore
a virtual server in a few seconds.
NOTE These snapshots allow you to test new applications and service packs before deploying them
to the organization.
Virtualization Types
Storage virtualization can be implemented the following three ways:
• Host based
• Storage device based
• Network based
This section examines all three.
Host Based
Host-based virtualization occurs on a user’s PC. It uses physical disks on the host system
and is managed by software just above the physical device that performs metadata lookup.
Most operating systems have their own form of host-based storage virtualization. In
Windows it’s called Logical Disk Manager and was introduced with Windows 2000.
Pros
• No additional hardware (aside from extra disk volumes) is required.
• It’s simple to implement.