upd doc on disk and partition denomination. set example for LVM LUKS …

…on a plain disk.

Signed-off-by: corbolais <corbolais@gmail.com>

doc/fai-guide.txt

@@ -1409,7 +1409,8 @@ The format of the disk configuration is similar to a fstab file.
 
 The partitioning tool `setup-storage(8)` performs all commands
 necessary for creating the disk partition layout, software RAID, LVM
-and for creating the file systems. Read the manual page of
+and for creating the file systems. Disks and partitions may easily be 
+referenced by disk1.1, disk2.4 etc. Read the manual page of
 `setup-storage(8)` for a detailed description and some examples of the
 format.
 

man/setup-storage.8

@@ -17,7 +17,8 @@ Using FAI disk_config files,
 \fBsetup-storage\fP
 computes effective partition and volume sizes and executes the necessary
 commands to configure storage devices. It manages disk drives as well as RAID
-and LVM volumes plus encryption and tmpfs. It handles following
+and LVM volumes plus encryption and tmpfs. Disks and partitions are designated 
+by \fBdisk1.2\fP, \fBdisk3.1\fP etc. and may thus be referenced as such. It handles following
 filesystems: \fBext2/3/4\fP, \fBvFAT(FAT32)\fP, \fBmsdos(FAT16)\fP, \fBreiserFS\fP, \fBXFS\fP and
 \fBBTRFS\fP but is flexible enough to be extended to further types as well.
 Once the storage devices are prepared, an appropriate
@@ -365,6 +366,25 @@ luks    -        /dev/md1       -       -
 .fi
 .PP
 
+.TP
+Plain disk + LUKS + LVM2 example
+.sp
+.nf
+.ta 10n 20n 30n 40n 50n
+
+disk_config disk1 disklabel:gpt bootable:1 fstabkey:uuid align-at:1M
+primary - 100%  -       -
+
+disk_config cryptsetup
+luks:"passwd" - disk1.1 -       -
+
+disk_config lvm fstabkey:uuid
+vg vg1  disk1.1
+vg1-root     /  30%-     ext4    defaults,errors=remount-ro,noatime,rw
+.sp
+.fi
+.PP
+
 .TP
 tmpfs example
 .sp