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Possible Duplicate:
ext4 partition size / free space discrepancies

I am simply confused by some output I'm seeing. When I run "df -h" the lines that are confusing me are as follows:

Filesystem                     Size   Used   Avail  Use%
/dev/mapper/sysvg-lvvideos     293G   4.5G   274G   2%

When I run "vgdisplay" I get:

--- Volume group ---
VG Name               sysvg
System ID
Format                lvm2
Metadata Areas        2
Metadata Sequence No  8
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                4
Open LV               4
Max PV                0
Cur PV                2
Act PV                2
VG Size               1.01 TiB
PE Size               4.00 MiB
Total PE              265251
Alloc PE / Size       120508 / 470.73 GiB
Free PE / Size        144743 / 565.40 GiB
VG UUID               4TjHj7-11CY-auM2-h05h-BXSV-2S4X-WUDh5R

When I run "lvdisplay sysvg" I get:

--- Logical volume ---
LV Name                /dev/sysvg/lvvideos
VG Name                sysvg
LV UUID                ZXNPP0-2IUI-UT1s-3riN-fxZH-QmfW-3OgwPI
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                293.00 GiB
Current LE             75008
Segments               2
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           254:2

What I don't get is: 293 - 4.5 does NOT equal 274. I have 14.5 GiB unaccounted for.

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You are right. I could have found my answer there as well. When I searched my issue before posting, I didn't see that one as I didn't use the right search keywords. But thanks for pointing out the duplicity. Reading that was very informative. :-) –  Jason Nov 20 '12 at 20:19
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marked as duplicate by psusi, Gilles, Jorge Castro, ajmitch, fossfreedom Nov 20 '12 at 23:14

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1 Answer

up vote 1 down vote accepted

Thats because normally 5% of the space is reserved for the root user.

you can disable that by

tune2fs -m0 /dev/sysvg/lvvideos

EDIT

that has nothing to do with LVM, that's a "feature" of the chosen filesystem...

EDIT2

The manpage of mke2fs states the following

   -m reserved-blocks-percentage
          Specify the percentage of the filesystem blocks reserved for the
          super-user.   This  avoids  fragmentation, and allows root-owned
          daemons, such as syslogd(8), to continue to  function  correctly
          after non-privileged processes are prevented from writing to the
          filesystem.  The default percentage is 5%.

So yes that applies to all ext2/ext3/ext4 partitions.

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So, as a "feature" of that filesystem...any partition I create using ext4 is going to reserve 5% for the root user? I ask because this result is the same for all my ext4 partitions. –  Jason Nov 20 '12 at 19:29
    
Yes, check the edited answer for an explanation... –  rbtux Nov 20 '12 at 19:32
    
Awesome. Thank you so much. I was off thinking I had to change the size of my Physical Extents...I never would have figured that out. :-) Thanks. –  Jason Nov 20 '12 at 19:36
    
Glad to help. If an answer is helpful you should accept it, so other users know it did actually fixed your problem... –  rbtux Nov 20 '12 at 20:22
    
How do I accept it? I feel silly asking, but this is my first time here. –  Jason Nov 20 '12 at 23:07
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