Information Technology Reference
In-Depth Information
and operational mandates against the maximum amount of data that can
possibly be logged and maintained. Logged information is a two-edged
sword, in that it can be legally subpoenaed as evidence but consumes
network, CPU, storage, and media resources faster than a college student
with a gigabit line straight to the campus DVD collection.
It is very important for the architect to identify meaningful data to be
logged and stored, because logging cannot be performed after the fact. If
an attack has already occurred, turning on network access logging will
do as much good as letting horses out of their stables after the barn has
already burned down.
E-mail
E-mail presents one of the most volatile data storage requirements in a
network enterprise. This information, which is vital to operational con-
trol and communications, must be available at a moment's notice yet be
protected against viruses, spam, and unauthorized access. E-mail mes-
sages can contain attachments of additional content, from funny back-
ground images of ducks and bunnies to viral programs or architectural
diagrams. Without imposed per-message size limits, entire movies can be
attached to individual e-mail messages. If someone e-mails a copy of the
latest company picnic video to
allstaff@somecorp.com
, the storage require-
ments can skyrocket in a moment's time as a thousand copies of the video
flood into the mail server's file storage.
E-mail can originate both locally and remotely, or it may be des-
tined for other locations and remain resident on an SMTP host only
long enough for its next route to become available. Individual organiza-
tions may receive millions of e-mail messages every day, consuming huge
amounts of storage just to facilitate e-mail processing queues. Individual
users may also decide to keep interesting messages (“interesting” often
meaning “all messages ever received”) until the end of time, causing a
never-ending cycle of continually accelerating storage expansion as file
sizes continue to grow according to Kryder's law.
Repositories
A similar cycle of expansion affects user file storage, nowhere more
so than in file repositories that allow for version control and recovery.
