Directory Structure - Red Hat ENTERPRISE LINUX 4 - INTRODUCTION TO SYSTEM ADMINISTRATION Administration Manual

Chapter 5. Managing Storage
Various file systems may extend the list to include other actions such as deleting, or even the ability
to make changes related to a file's access control.
5.5.2.5. Accounting of Space Utilized
One constant in a system administrator's life is that there is never enough free space, and even if there
is, it will not remain free for long. Therefore, a system administrator should at least be able to easily
determine the level of free space available for each file system. In addition, file systems with well-
defined user identification capabilities often include the capability to display the amount of space a
particular user has consumed.
This feature is vital in large multi-user environments, as it is an unfortunate fact of life that the 80/20
rule often applies to disk space — 20 percent of your users will be responsible for consuming 80
percent of your available disk space. By making it easy to determine which users are in that 20 percent,
you can more effectively manage your storage-related assets.
Taking this a step further, some file systems include the ability to set per-user limits (often known as
disk quotas) on the amount of disk space that can be consumed. The specifics vary from file system to
file system, but in general each user can be assigned a specific amount of storage that a user can use.
Beyond that, various file systems differ. Some file systems permit the user to exceed their limit for one
time only, while others implement a "grace period" during which a second, higher limit is applied.

5.5.3. Directory Structure

Many system administrators give little thought to how the storage they make available to users today
is actually going to be used tomorrow. However, a bit of thought spent on this matter before handing
over the storage to users can save a great deal of unnecessary effort later on.
The main thing that system administrators can do is to use directories and subdirectories to structure
the storage available in an understandable way. There are several benefits to this approach:
More easily understood
•
More flexibility in the future
•
By enforcing some level of structure on your storage, it can be more easily understood. For example,
consider a large mult-user system. Instead of placing all user directories in one large directory, it
might make sense to use subdirectories that mirror your organization's structure. In this way, people
that work in accounting have their directories under a directory named
in engineering would have their directories under
The benefits of such an approach are that it would be easier on a day-to-day basis to keep track of the
storage needs (and usage) for each part of your organization. Obtaining a listing of the files used by
everyone in human resources is straightforward. Backing up all the files used by the legal department
is easy.
With the appropriate structure, flexibility is increased. To continue using the previous example, assume
for a moment that the engineering department is due to take on several large new projects. Because
of this, many new engineers are to be hired in the near future. However, there is currently not enough
free storage available to support the expected additions to engineering.
However, since every person in engineering has their files stored under the
it would be a straightforward process to:
Procure the additional storage necessary to support engineering
•
Back up everything under the
•
engineering
directory
engineering
, people that work
accounting
, and so on.
engineering
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directory,