Prepare a single disk or a disk raid:

mkfs.ext3 <phsvol>
lvm
lvm> pvcreate <physvol>
lvm> vgcreate <physvol> // or several physical volumes: <physvol1> <physvol2> <physvol3>
lvm> lvcreate <volgroup> <physical>
lvm> quit
mkfs.ext3 /dev/mapper/<volgroup-logvol>
mount /dev/mapper/<volgroup-logvol> <dir>

Auto-mount during boot:

vim /etc/fstab
/dev/mapper/<volgroup-logvol> <dir> ext3 noatime,user_xattr 0 0