Linux primary partition, extended partition, logical partition

Under the Linux system (other operating systems have similar provisions), the partition of the disk can be broadly divided into three categories, mainly partition, extended partition and logical partition, and so on. Linux system administrators must make a reasonable plan for the three partitions when they deploy the system, otherwise they will waste valuable hard disk space.

Typically, you can split up to four primary partitions in one hard disk. Because the partition table in the hard disk is only 64Bytes in size, partitioning a partition requires 16Bytes space to store information about the partition. Due to the size limit of this partition table, the hard disk can be divided into four primary partitions. If a hard disk has 120 g at this time, and the administrator divides 4 primary partitions, the space for each primary partition is 20 g. So it took a total of 80G space. The remaining 40G space on this drive will not be available. This obviously wastes space on the hard drive.

To break the limit of up to four primary partitions, the Linux system introduces the concept of extended partitioning. That is, the administrator can set one of the primary partitions as an extended partition (note that only one extended partition can be used) for expansion. In the extended partition, you can create multiple logical partitions. In other words, an extended partition cannot be used directly, and it must be subdivided into logical partitions before it can be used to store data. Typically, the starting and ending positions of logical partitions are recorded in the first sector of each logical partition, which is also called an extended partition table. Under the extended partition, the system administrator can set up multiple logical partitions according to the actual situation, and cut an extended subdivision into multiple areas for use.

So with the help of extended partition and logical partitioning, a hard disk can be divided into six, seven, or more partitions. Sometimes due to the need for disk quotas, to different users or applications corresponding to different partitions. The planning of the user's home directory, which also requires a separate partition. Therefore, the system administrator needs before deploying the system, first consider the system in the end of a few areas appropriate. This is how the hard disk partition space is planned, which is a question that the system administrator needs to answer before deploying the Linux system.

Linux primary partition, extended partition, logical partition