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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.
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