Hard Drive Partitions

By Joshua Erdman
Digital Foundation, inc.

Partitions are used to declare sections of the hard drive as usable space. All the space can be consumed by a single partition, or it can divided up into multiple partitions of various sizes.

With Microsoft operating systems, each partition ends up being a different drive letter. Thus displaying multiple logical drives. In Linux all file references start from the root or '/'. So a partition is referenced as either the root folder or can be any subfolder off the root folder.

Purposes for Partitions

Preserving Space

Preserving space for the operating system is a great reason to use partitions. If your operating system resides on a single partition and that same partition is used for storing important data and also stores transaction logs there is a chance that the logs may fill the whole drive. Now there is no space available for the really important data.

File Fragmentation

You can think of files being stored on a hard drive just like taking notes on a blank piece of paper, the data is written sequentially and you have a limited amount of space. Now imagine that you have no memory and all that you must remember can only be stored on this piece of paper. Of course you would write with a pencil so you could erase information that was no longer important. Also your paper would probably get close to full. As you erased bits of data from your paper, new information may need to be scattered across these empty little spaces. This new data becomes "fragmented".

This fragementation results in poor performance because the computer must skip around to retrieve all the bits of the needed file. Read our article on defragmenting your harddrive for more information.

Partitions for each data type

So with computers it is common to create separate partitions for different data types. One partition for small files that may be deleted often and another partition for larger data files that you do not want to get fragemented as they are written or as they grow. A good example of small files would be log files, transaction files (for a database server or mail server), or temporary files. The larger files would include Database files (not only are these large but they grow) and media files (such as audio and video clips).

Partition Performance

Remember that even though you may partition a drive, the partitions on that drive must share the bandwidth (throughput) available to that drive. If you need greater speed, separate the data for these partitions on different drives.