Chapter 5. Managing Storage

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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 will be able to 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 will have their directories under a directory named

accounting

, people that

work in engineering would have their directories under

engineering

, and so on.

The benefits of such an approach would be that it would be easier on a day to day basis to keep track

of the storage needs (and usage) of 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 will be hired in the near future. However, there is not enough free storage

available to support the expected additions to engineering.

However, since every person in engineering has their files stored under the

Engineering

directory,

it would be a straightforward process to:

Procure the additional storage necessary to support Engineering

Back up everything under the

Engineering

directory

Restore the backup onto the new storage

Rename the

Engineering

directory on the original storage to something like

Engineering 

archive

(before deleting it entirely after running smoothly with the new configuration for a month)

Make the necessary changes so that all Engineering personnel can access their files on the new

storage

Of course, such an approach does have its shortcomings. For example, if people frequently move

between departments, you must have a way of being informed of such transfers, and modify the

directory structure appropriately. Otherwise, the structure will no longer reflect reality, which will

make more work   not less   for you in the long run.