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What seems to be the problem? End users care about what is stored. IT cares
about how it is stored. For the most part, IT hasn't had to worry about the
format in which data was stored. The application that created the data could
be counted on to be able to read the data. But what about a world of data de-duplication,
compression, and encryption where the bits are laid out on disk or tape in a
pattern that is different than the application is expecting. The application
still needs to be able to use the data, but needs some help in being able to
do so. The challenge to IT is to make sure data de-duplication, compression,
and encryption are performed in the proper order so that you can get the benefits
of each and still be able to use the data.

What do you need to know? Why do you want to mess around with how the bits
are laid out on disk or tape in the first place? Well, data de-duplication and
compression are about the better use of storage assets and encryption is about
better data security. Both better asset utilization and better data security
are important benefits.

The net result of using data de-duplication and/or compression is that less
storage is required. Yes, both disk and tape storage are relatively inexpensive
compared to what they were even a few years ago, but storage is still not free.
Moreover, demands for storing more data seems to be increasing faster than the
rate at which the price of storage is falling. In addition to savings in the
cost of storage itself, saving on power and cooling for disk can also be important.
So taking advantage of data de-duplication and compression where appropriate
is likely to become more commonplace.

The emphasis on preserving data confidentiality is increasing and encryption
is a key technology in ensuring data confidentiality. Encrypting data in flight
is a no brainer (since you don't have to worry about key management and there
isn't likely to be a significant performance penalty if any at all). A strong
case for encrypting data at rest on tape can be made because tape is removable
media and removable media can be lost or stolen. Perhaps surprisingly, data
on disk -- and that means on arrays and not only laptops and desktops -- will
eventually become encrypted at rest. Now theoretically, not all data in a disk
array may need encryption protection, but if any part of the array needs to
be encrypted, then simply protecting all of the data with encryption will become
the path of least resistance.

So sooner or later you are going to buy into technologies that manipulate the
layout of bits on storage media. And you had better make sure that the different
technologies are employed in the right order.

The first goal is to make sure that your data remains useful for use by an
application, a query tool, or by an e-discovery tool as appropriate. Encryption
must be employed last. Encryption, for all practical purposes, randomizes a
bit stream of data so any efforts at data de-duplication or compression would
be rendered useless.

Data de-duplication goes first to eliminate inter-file or inter-block redundancies.
Then compression can be applied to squeeze data further and then, and only then,
can encryption be applied. If all three are applied correctly, you can derive
the benefits of each and still be able to use your data.

What can you do about it? As time goes on, the need to use data de-duplication,
compression, and encryption will grow. You will succumb to using these technologies
as appropriate as the benefits become irresistible. But that means that you
need to employ each of these technologies carefully and you had better make
sure that all of the technologies work in concert with one another. You want
the technologies to give you benefits, not headaches. So the order of application
is important. Make sure that everything works together.

» posted by jnaze

Mesabi Group

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