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1 ATA over Ethernet is a network protocol that provides simple access to
2 block storage on the LAN.
6 The EtherDrive (R) HOWTO for users of 2.6 kernels is found at ...
10 It has many tips and hints!
12 The aoetools are userland programs that are designed to work with this
13 driver. The aoetools are on sourceforge.
17 The scripts in this Documentation/aoe directory are intended to
18 document the use of the driver and are not necessary if you install
19 the aoetools.
22 CREATING DEVICE NODES
24 Users of udev should find the block device nodes created
25 automatically, but to create all the necessary device nodes, use the
26 udev configuration rules provided in udev.txt (in this directory).
28 There is a udev-install.sh script that shows how to install these
29 rules on your system.
31 There is also an autoload script that shows how to edit
32 /etc/modprobe.conf to ensure that the aoe module is loaded when
33 necessary. Preloading the aoe module is preferable to autoloading,
34 however, because AoE discovery takes a few seconds. It can be
35 confusing when an AoE device is not present the first time the a
36 command is run but appears a second later.
38 USING DEVICE NODES
40 "cat /dev/etherd/err" blocks, waiting for error diagnostic output,
41 like any retransmitted packets.
43 "echo eth2 eth4 > /dev/etherd/interfaces" tells the aoe driver to
44 limit ATA over Ethernet traffic to eth2 and eth4. AoE traffic from
45 untrusted networks should be ignored as a matter of security. See
46 also the aoe_iflist driver option described below.
48 "echo > /dev/etherd/discover" tells the driver to find out what AoE
49 devices are available.
51 In the future these character devices may disappear and be replaced
52 by sysfs counterparts. Using the commands in aoetools insulates
53 users from these implementation details.
55 The block devices are named like this:
60 ... so that "e0.2" is the third blade from the left (slot 2) in the
61 first shelf (shelf address zero). That's the whole disk. The first
62 partition on that disk would be "e0.2p1".
64 USING SYSFS
66 Each aoe block device in /sys/block has the extra attributes of
67 state, mac, and netif. The state attribute is "up" when the device
68 is ready for I/O and "down" if detected but unusable. The
69 "down,closewait" state shows that the device is still open and
70 cannot come up again until it has been closed.
72 The mac attribute is the ethernet address of the remote AoE device.
73 The netif attribute is the network interface on the localhost
74 through which we are communicating with the remote AoE device.
76 There is a script in this directory that formats this information in
77 a convenient way. Users with aoetools should use the aoe-stat
80 root@makki root# sh Documentation/aoe/status.sh
81 e10.0 eth3 up
82 e10.1 eth3 up
83 e10.2 eth3 up
84 e10.3 eth3 up
85 e10.4 eth3 up
86 e10.5 eth3 up
87 e10.6 eth3 up
88 e10.7 eth3 up
89 e10.8 eth3 up
90 e10.9 eth3 up
91 e4.0 eth1 up
92 e4.1 eth1 up
93 e4.2 eth1 up
94 e4.3 eth1 up
95 e4.4 eth1 up
96 e4.5 eth1 up
97 e4.6 eth1 up
98 e4.7 eth1 up
99 e4.8 eth1 up
100 e4.9 eth1 up
102 Use /sys/module/aoe/parameters/aoe_iflist (or better, the driver
103 option discussed below) instead of /dev/etherd/interfaces to limit
104 AoE traffic to the network interfaces in the given
105 whitespace-separated list. Unlike the old character device, the
106 sysfs entry can be read from as well as written to.
108 It's helpful to trigger discovery after setting the list of allowed
109 interfaces. The aoetools package provides an aoe-discover script
110 for this purpose. You can also directly use the
111 /dev/etherd/discover special file described above.
113 DRIVER OPTIONS
115 There is a boot option for the built-in aoe driver and a
116 corresponding module parameter, aoe_iflist. Without this option,
117 all network interfaces may be used for ATA over Ethernet. Here is a
118 usage example for the module parameter.
120 modprobe aoe_iflist="eth1 eth3"
122 The aoe_deadsecs module parameter determines the maximum number of
123 seconds that the driver will wait for an AoE device to provide a
124 response to an AoE command. After aoe_deadsecs seconds have
125 elapsed, the AoE device will be marked as "down". A value of zero
126 is supported for testing purposes and makes the aoe driver keep
127 trying AoE commands forever.
129 The aoe_maxout module parameter has a default of 128. This is the
130 maximum number of unresponded packets that will be sent to an AoE
131 target at one time.
133 The aoe_dyndevs module parameter defaults to 1, meaning that the
134 driver will assign a block device minor number to a discovered AoE
135 target based on the order of its discovery. With dynamic minor
136 device numbers in use, a greater range of AoE shelf and slot
137 addresses can be supported. Users with udev will never have to
138 think about minor numbers. Using aoe_dyndevs=0 allows device nodes
139 to be pre-created using a static minor-number scheme with the
140 aoe-mkshelf script in the aoetools.