LVM functions in linux

Understand LVM management in Linux: LVM is short for LogicalVolumeManager (logical volume management). It is a mechanism for managing disk partitions in Linux, it can create a virtual disk volume Group (VG) on multiple physical volumes (PVS), and then create a logical volume (LV) on the disk volume group ), to break through some restrictions imposed by traditional partitions, we need to first understand the limitations imposed by traditional partitions and then understand how LVM can break through these limits. First, understand how to use data transfer

Understand LVM management in Linux:

LVM is short for LogicalVolume Manager (logical volume management). It is a mechanism for managing disk partitions in Linux. it can be deployed on multiple physical volumes (PVS) create a virtual disk volume Group (VG) on the disk volume group, and then create a logical volume (LV) on the disk volume group to break through some restrictions imposed by traditional partitions, so we need to better understand LVM, first, you need to understand the limitations of traditional partitions, and then understand how LVM can break through these restrictions.

First, understand the restrictions on using traditional partitions:

Different partitions are relatively independent, and the utilization of each partition space is very unbalanced. for example, one partition is almost full, but another partition has a large capacity. When a partition storage is full, it cannot be flexibly expanded. if you want to resize the partition, you can only use this to be full, or the data in the already filled partition is copied to another storage device, and then the partition is re-planned to create a file system again, which is very troublesome. This process requires data backup and recovery. to sum up, you cannot perform Incremental resizing on traditional partitions. The so-called Incremental resizing is a 50 gb d partition, this time, we need to resize the D partition to 70 GB, and then scale it from 70 GB to 90 GB next time. in this process, we do not need to re-plan the partition table and format the partition.

LVMBreaking the concept of traditional partitioning:

As shown in Figure 1: it breaks through the features of independent partitions on traditional hard disks. it splits several different physical volume PVS (in fact, sdb1 and sdc1 in the physical partition ratio ), plan to form a virtual volume Group (VG), the so-called virtual volume Group (VG) in fact, it is equivalent to organizing the free space on the physical volumes distributed in sdb1 and sdc1 into an overall virtual hard disk (also called virtual volume group VG), and then on this virtual hard disk (virtual volume group VG) re-planning the logical volume (LV) is equivalent to re-planning the partition on the virtual hard disk, and re-planning the partition (Logical Volume LV), which features Incremental resizing, for example, a logical volume is initially planned to be 10 GB. when the capacity is insufficient, you only need to use the relevant commands to increase the capacity of the initial 10 GB logical volume to 15 GB, during the entire capacity increase process, you no longer need to back up the data on the volume, format the data, and finally restore the data to the volume. VLM saves the tedious process of resizing the traditional partition, higher efficiency!