Fedora Linux

Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/main/multimedia: 11/117248 files (9.1% non-contiguous), 8043/262144 blocks

Now use resize2fs to reduce the size of the filesystem:

# resize2fs /dev/main/multimedia 740M
resize2fs 1.38 (30-Jun-2005)
Resizing the filesystem on /dev/main/multimedia to 189440 (4k) blocks.
The filesystem on /dev/main/multimedia is now 189440 blocks long.

Note that resize2fs expects the size to be the second argument (there is no -- size option as there is with the LVM commands).

The LVM commands accept sizes containing decimals (such as 1.2G), but resize2fs does not; use the next smaller unit to eliminate the decimal point (1200M). 

Both the filesystem commands and the LVM commands round off sizes to the closest multiple of their internal allocation units. This means that resize2fs and lvreduce may interpret a size such as 750M slightly differently. In order to avoid the potential disaster of resizing the LV to be smaller than the filesystem, always resize the filesystem so that it is slightly smaller than the planned LV size, resize the LV, and then grow the filesystem to exactly fill the LV. In this case, I'm resizing the filesystem to 740 MB and will resize the LV to 750 MB.

Now that the filesystem has been resized, you can shrink the logical volume:

# lvreduce /dev/main/multimedia --size 750M
Rounding up size to full physical extent 752.00 MB
WARNING: Reducing active logical volume to 752.00 MB
THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce multimedia? [y/n]: y
Reducing logical volume multimedia to 752.00 MB
Logical volume multimedia successfully resized

Finally, grow the filesystem to completely fill the logical volume:

# resize2fs /dev/main/multimedia
resize2fs 1.38 (30-Jun-2005)
Resizing the filesystem on /dev/main/multimedia to 192512 (4k) blocks.
The filesystem on /dev/main/multimedia is now 192512 blocks long.

6.1.1.3.5. Creating a new logical volume

The lvcreate command will create a new volume:

# lvcreate main -- name survey --size 5G
Logical volume 'survey' created

Next, add a filesystem:

# mkfs -t ext3 - L survey -E resize= 20G /dev/main/survey
mke2fs 1.38 (30-Jun-2005)
Filesystem label=survey
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
655360 inodes, 1310720 blocks
65536 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=8388608
40 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.

The -t ext3 option specifies the filesystem type, -L survey specifies a optional filesystem volume label (to identify the contents), and -E resize= 20G (also optional) configures a block group descriptor table large enough that the filesystem can be grown up to 20 GB while mounted. In this case, 20 GB is four times the initial size of the filesystem; use whatever upper limit seems reasonable for your application (the table will take roughly 4 KB of space for each gigabyte in the filesystem maximum size, so the overhead is minimal).

You can now mount the filesystem and use it. Here I'll use /usr/lib/survey as the mount point:

# mkdir /usr/lib/survey
# mount /dev/main/survey /usr/lib/survey

To configure the Fedora system to mount this filesystem every time it is booted, add an entry to the file /etc/fstab :

/dev/main/root / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
devpts /dev/pts devpts gid=5,mode=620 0 0