EXT3 fajl sistem po default-u uzima 5% rezervisanog prostora, što je za današnje sisteme malo mnogo, naročito kad su u pitanju Tb podataka. Ako ne želite da izgubite 33 Gb na recimo 500Gb sa default ex3 fajlsistemom, onda čitaj dalje:

# vgdisplay
 --- Volume group ---
 VG Name               test
 System ID             
 Format                lvm2
 Metadata Areas        1
 Metadata Sequence No  1
 VG Access             read/write
 VG Status             resizable
 MAX LV                0
 Cur LV                0
 Open LV               0
 Max PV                0
 Cur PV                1
 Act PV                1
 VG Size               500.00 GB
 PE Size               16.00 MB
 Total PE              32000
 Alloc PE / Size       0 / 0   
 Free  PE / Size       32000 / 500.00 GB
 VG UUID               4ZKCUa-yLd7-WMSn-OIzA-2XS1-RAvJ-ny1QS5

# lvcreate --size 500G --name test test
 Logical volume "test" created

# mkfs.ext3 /dev/mapper/test-test
mke2fs 1.41.9 (22-Aug-2009)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
32768000 inodes, 131072000 blocks
6553600 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=4294967296
4000 block groups
32768 blocks per group, 32768 fragments per group
8192 inodes per group
Superblock backups stored on blocks:
 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968,
 102400000

Writing inode tables: done                            
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 21 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

# mount /dev/mapper/test-test /test

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/test-test 493G  198M  467G   1% /test                <<<< WTF?!

# umount /test

# tune2fs -m 0.2 /dev/mapper/test-test
tune2fs 1.41.9 (22-Aug-2009)
Setting reserved blocks percentage to 0.2% (262144 blocks)

# mount /dev/mapper/test-test /test
# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/test-test 493G  198M  491G 1% /test

Naravno, pre bilo kakve akcije, RTFM tune2fs. Lično ne koristim ex3 fs nigde, ali me je tweet o ovoj temi kao i razgovor sa momsab-om kopkao da vidim koliko on zaista jede prostora.