I usually prefer the graphical way with gparted , it is possible find this useful command in a live disk of ubuntu or knoppix
but in amazon use this approach is a bit tricky so I learn another way with the command resize2fs. Anyway the graph interface is always preferable if you can use it.
I found two guides one with fdisk (https://codesilence.wordpress.com/2013/03/14/live-resizing-of-an-ext4-filesytem-on-linux/ ) the other with parted (http://www.gnu.org/software/parted/manual/html_node/parted_31.html)
the parted approach didn't work well for me with ubuntu 12.04 so I used with success the fisk method
staring point
df -h
/dev/xvdf1 99G 94G 26M 100% /var/hg/repos
Fdisk delete a partition
this is the scary part if you don't do the makefs command the data will be not deleted. You need of course to recreate a good partition
enter in the disk
fdisk /dev/xvdf
it is very importat use the device not the partition in the above command fdisk /dev/xvdf1 IT IS WRONG!!!!
visualize , delete , visualize
Command (m for help): p
Disk /dev/xvdf: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders, total 419430400 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000828a9
Device Boot Start End Blocks Id System
/dev/xvdf1 2048 390625279 195311616 83 Linux
Command (m for help): d
Selected partition 1
Command (m for help): p
Disk /dev/xvdf: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders, total 419430400 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000828a9
Device Boot Start End Blocks Id System
create a new partition
Command (m for help): n
Partition type:
p primary (0 primary, 0 extended, 4 free)
e extended
Select (default p): p
Partition number (1-4, default 1):
Using default value 1
First sector (2048-419430399, default 2048):
Using default value 2048
Last sector, +sectors or +size{K,M,G} (2048-419430399, default 419430399):
Using default value 419430399
resize
resize2fs /dev/xvdf1
resize2fs 1.42 (29-Nov-2011)
Filesystem at /dev/xvdf1 is mounted on /var/hg/repos; on-line resizing required
old_desc_blocks = 7, new_desc_blocks = 13
Performing an on-line resize of /dev/xvdf1 to 52428544 (4k) blocks.
The filesystem on /dev/xvdf1 is now 52428544 blocks long.
ending point
/dev/xvdf1 197G 94G 94G 50% /var/hg/repos