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: LVM Terminology:

VGDA

The same as non-LVM system that stores meta data containing partitions information in the disk label situated at the beginning of disk, logical volumes and meta data related to volume groups are stored in VGDA (Volume Group Descriptor Area) at the beginning position of physical volumes. VGDA includes the following contents: PV descriptor, VG descriptor, LV descriptor and some PE descriptors.

Starting up a LVM system, the system activates VGs and loads VGDA to internal memory so as to identify LV's real physical storage position. When the system runs I/O operation, it will visit real physical storage position based on the reflection mechanism constructed by VGDA.


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