[SOLVED] dm-crypt LUKS volume missing almost 20 Gb of free space

speed145a · 2010-12-06 18:03:36

After converting to a dm-crypt volume I seem to be missing almost 20Gb from my free space.

I've recently replaced the HDD in my laptop due to a failure of the old one so I've started from scratch. I installed without encryption a week ago, then yesterday I backed up all my data and reinstalled using an encrypted /home

It is set up as dm-crypt LUKS with no LVM. My HDD is partitioned as logical partitions as follows:
sda5: /boot
sda6: /
sda7: /home (dm-crypt) - mapped from /dev/mapper/sda7crypt - formatted to ext4
sda8: SWAP

so here's what df -h shows:

Filesystem            Size  Used Avail Use% Mounted on
udev                   10M  228K  9.8M   3% /dev
/dev/sda6              12G  5.4G  5.7G  49% /
shm                   1.9G     0  1.9G   0% /dev/shm
/dev/sdb1             116M  1.6M  108M   2% /mnt/keys
/dev/mapper/sda7crypt   378G   29G  330G   9% /home
/dev/sda5             194M   34M  151M  19% /boot

my question is: is that normal? if not, where did it go?

Last edited by speed145a (2010-12-08 22:02:27)

speed145a · 2010-12-07 21:13:38

Do I need to provide more information?

foutrelis · 2010-12-07 21:41:04

The only explanation that makes sense is reversed blocks. It's the filesystem that's keeping 5% of the available space only to be used by root and doesn't have anything to do with LUKS.

Here's a post discussing the situation in more detail. Instead of '-m 1', use '-m 0'; no point in reserving space in non-critical partitions like one that houses /home.

speed145a · 2010-12-07 21:51:03

Thank you so much! Here is the result for those who care.

[jonathan@temple ~]$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/sda7crypt
                      378G   30G  330G   9% /home

[root@temple jonathan]# tune2fs -m 0 /dev/mapper/sda7crypt
tune2fs 1.41.12 (17-May-2010)
Setting reserved blocks percentage to 0% (0 blocks)
[root@temple jonathan]# df -h
Filesystem            Size  Used Avail Use% Mounted on

/dev/mapper/sda7crypt
                      378G   30G  349G   8% /home

*speed145a skipps along along his merry way with an extra 19 GB of space

Arch Linux

#1 2010-12-06 18:03:36

[SOLVED] dm-crypt LUKS volume missing almost 20 Gb of free space

#2 2010-12-07 21:13:38

Re: [SOLVED] dm-crypt LUKS volume missing almost 20 Gb of free space

#3 2010-12-07 21:41:04

Re: [SOLVED] dm-crypt LUKS volume missing almost 20 Gb of free space

#4 2010-12-07 21:51:03

Re: [SOLVED] dm-crypt LUKS volume missing almost 20 Gb of free space

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