Information Technology Reference
In-Depth Information
Individual files can take up storage capacity quickly, but storage within
a versioned file repository can expand fantastically when each version of
a saved file is maintained separately. Portal systems that include docu-
ment management features for version control provide a much more ver-
satile mechanism for collaborative communication than simple shared
folders with a single copy of a living document, at the cost of a vastly
expanded storage requirement to store new copies of a file every time
the file is checked back in or changes are saved. Similarly, file storage
that includes automated backup and recovery options must also include
adequate storage to meet whatever recovery threshold an organization
establishes. The longer the backup recovery period maintained (say, up
to two weeks back versus up to a month back), the finer the resolution
for recovery (once an hour versus once a week), and the speed of recovery
(full backups each time versus a single full backup and multiple incre-
mental backups) all affect the total storage required for file recovery and
disaster recovery support. We will review specific backup solutions later
in this chapter.
Virtual Computers
As virtualization mechanisms become more prevalent, the storage require-
ments for virtual systems and processes continue to grow. Chapter 9 will
focus on the benefits of virtualization in the network enterprise, but an
architect must ensure that adequate storage capacity is available not only
for the virtualized system but also for the source system images, spawned
duplicates, differencing files, and other system copies maintained for
disaster recovery, testing, and load balancing. Because a virtualized com-
puter is nothing more than a large file, the ease of virtualization can lead
to significant requirements for additional storage on virtualization hosts.
Storage Policies
Storage capacity faces a constant threat posed by the ever-increasing flood
of information pouring into local and central file stores throughout a net-
work enterprise. Before planning can begin for physical storage require-
ments, the architect must identify all existing mandates and develop basic
data storage policies. It is simply not reasonable for all users to have an
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