What is extent size in volume groups? I have a very small volume, like 5mb, I need to set an appropriate extent size, but I do not know what it is.
It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.
The physical extent (PE) size is the basic unit out of which logical volumes are created. It defines the minimum size of a volume and the possible increments (having a 4MB PE size would mean the minimum volume size is 4MB and you can grow it in 4MB increments).
Making the PE too small wouldn't be recommended, as the maximum volume size is 65,536 PEs, so if you reduce this to 1MB, you end up with volumes not larger than 64GB.