Allocation group
An AG or allocation group is a subvolume in a file system which maintains its own track of free blocks and file data.
This makes simultaneous file operations possible; only one write can happen to an AG at any time, but multiple operations can be performed on the file system, each happening in a different AG. In SMP systems multiple CPUs can write to different AGs, enabling physically concurrent disk operations on a single file system..
Used by these file systems:
