So after some searching around these forums I didn't find an answer that I was looking for.

My question is simple, when resizing (or creating) a Linux Logical Volume, how can I get the partition to be an EXACT amount.

Here is what I am talking about:


[root@tuxedo /]# lvscan
ACTIVE '/dev/vg_test/lv_test' [800.00 MiB] inherit

I want my LV to be 800MB. Which it says it is. Here's an output of my df -h

/dev/mapper/vg_test-lv_test
786M 34M 714M 5% /test

No matter what I do, I cannot get my partition to be exactly 800 like desired. Can anyone help?

All file systems have some overhead which is why the volume size differs from the output of df. You can try increasing the LV size by the overhead percentage which may get to the desired 800M. There filesystem parameters that can be tweaked like journal size if using ext3/4 that can change overhead size.

Is there any reason why you want exactly 800M.


http://rwmj.wordpress.com/2009/11/08...data-overhead/

Thank you for the reply.

The only reason I was looking for an exact number is because I will be taking the RHCSA exam here on the 9th of next month, and one of the objectives is to resize an LVM to a desired amount.

I figured on the test it would need to be the exact amount they request?

I do not know but would guess it is volume size vs filesystem size.

I think that would make sense.

Thank you again!