aoe: update documentation to better reflect aoe-plus-udev usage

ATA over Ethernet is a network protocol that provides simple access to

block storage on the LAN.

  http://support.coraid.com/documents/AoEr11.txt

The EtherDrive (R) HOWTO for 2.6 and 3.x kernels is found at ...

  http://support.coraid.com/support/linux/EtherDrive-2.6-HOWTO.html

  There is a udev-install.sh script that shows how to install these

  rules on your system.

  If you are not using udev, two scripts are provided in

  Documentation/aoe as examples of static device node creation for

  using the aoe driver.

    rm -rf /dev/etherd

    sh Documentation/aoe/mkdevs.sh /dev/etherd

  ... or to make just one shelf's worth of block device nodes ...

    sh Documentation/aoe/mkshelf.sh /dev/etherd 0

  There is also an autoload script that shows how to edit

  /etc/modprobe.d/aoe.conf to ensure that the aoe module is loaded when

  necessary.

  necessary.  Preloading the aoe module is preferable to autoloading,

  however, because AoE discovery takes a few seconds.  It can be

  confusing when an AoE device is not present the first time the a

  command is run but appears a second later.

USING DEVICE NODES

  "echo > /dev/etherd/discover" tells the driver to find out what AoE

  devices are available.

  These character devices may disappear and be replaced by sysfs

  counterparts.  Using the commands in aoetools insulates users from

  these implementation details.

  In the future these character devices may disappear and be replaced

  by sysfs counterparts.  Using the commands in aoetools insulates

  users from these implementation details.

  The block devices are named like this:

  The netif attribute is the network interface on the localhost

  through which we are communicating with the remote AoE device.

  There is a script in this directory that formats this information

  in a convenient way.  Users with aoetools can use the aoe-stat

  There is a script in this directory that formats this information in

  a convenient way.  Users with aoetools should use the aoe-stat

  command.

  root@makki root# sh Documentation/aoe/status.sh 

  usage example for the module parameter.

    modprobe aoe_iflist="eth1 eth3"

  The aoe_deadsecs module parameter determines the maximum number of

  seconds that the driver will wait for an AoE device to provide a

  response to an AoE command.  After aoe_deadsecs seconds have

  elapsed, the AoE device will be marked as "down".

  The aoe_maxout module parameter has a default of 128.  This is the

  maximum number of unresponded packets that will be sent to an AoE

  target at one time.

  The aoe_dyndevs module parameter defaults to 1, meaning that the

  driver will assign a block device minor number to a discovered AoE

  target based on the order of its discovery.  With dynamic minor

  device numbers in use, a greater range of AoE shelf and slot

  addresses can be supported.  Users with udev will never have to

  think about minor numbers.  Using aoe_dyndevs=0 allows device nodes

  to be pre-created using a static minor-number scheme with the

  aoe-mkshelf script in the aoetools.

#!/bin/sh

n_shelves=${n_shelves:-10}

n_partitions=${n_partitions:-16}

if test "$#" != "1"; then

	echo "Usage: sh `basename $0` {dir}" 1>&2

	echo "       n_partitions=16 sh `basename $0` {dir}" 1>&2

	exit 1

fi

dir=$1

MAJOR=152

echo "Creating AoE devnode files in $dir ..."

set -e

mkdir -p $dir

# (Status info is in sysfs.  See status.sh.)

# rm -f $dir/stat

# mknod -m 0400 $dir/stat c $MAJOR 1

rm -f $dir/err

mknod -m 0400 $dir/err c $MAJOR 2

rm -f $dir/discover

mknod -m 0200 $dir/discover c $MAJOR 3

rm -f $dir/interfaces

mknod -m 0200 $dir/interfaces c $MAJOR 4

rm -f $dir/revalidate

mknod -m 0200 $dir/revalidate c $MAJOR 5

rm -f $dir/flush

mknod -m 0200 $dir/flush c $MAJOR 6

export n_partitions

mkshelf=`echo $0 | sed 's!mkdevs!mkshelf!'`

i=0

while test $i -lt $n_shelves; do

	sh -xc "sh $mkshelf $dir $i"

	i=`expr $i + 1`

done

#! /bin/sh

if test "$#" != "2"; then

	echo "Usage: sh `basename $0` {dir} {shelfaddress}" 1>&2

	echo "       n_partitions=16 sh `basename $0` {dir} {shelfaddress}" 1>&2

	exit 1

fi

n_partitions=${n_partitions:-16}

dir=$1

shelf=$2

nslots=16

maxslot=`echo $nslots 1 - p | dc`

MAJOR=152

set -e

minor=`echo $nslots \* $shelf \* $n_partitions | bc`

endp=`echo $n_partitions - 1 | bc`

for slot in `seq 0 $maxslot`; do

	for part in `seq 0 $endp`; do

		name=e$shelf.$slot

		test "$part" != "0" && name=${name}p$part

		rm -f $dir/$name

		mknod -m 0660 $dir/$name b $MAJOR $minor

		minor=`expr $minor + 1`

	done

done

#! /bin/sh

# collate and present sysfs information about AoE storage

#

# A more complete version of this script is aoe-stat, in the

# aoetools.

set -e

format="%8s\t%8s\t%8s\n"