More lvm2 weirdness

I have just install lv,2 on my Ubuntu 9.10 instance on EC2. I go to create the logical volume and got the following

# lvcreate -L 1g -n data_vol data_vg

/proc/misc: No entry for device-mapper found

Is device-mapper driver missing from kernel?

Failure to communicate with kernel device-mapper driver.

/proc/misc: No entry for device-mapper found

Is device-mapper driver missing from kernel?

Failure to communicate with kernel device-mapper driver.

Incompatible libdevmapper 1.02.27 (2008-06-25)(compat) and kernel driver

striped: Required device-mapper target(s) not detected in your kernel

Run `lvcreate --help' for more information.

It turns out that after install some of the modules are not loaded, so you have to

# modprobe dm_mod

# modprobe dm_mirror

# modprobe dm_snapshot

After that the command executes correctly!

# lvcreate -L 1g -n data_vol data_vg

Logical volume "data_vol" created