.TH AOE 3 .SH NAME aoe \- AoE interface .SH SYNOPSIS .nf .B bind -a #æ /dev .B /dev/aoe/ctl .B /dev/aoe/log .BI /dev/aoe/ n.m /config .BI /dev/aoe/ n.m /ctl .BI /dev/aoe/ n.m /devlink/ \fI0\fR \&... .BI /dev/aoe/ n.m /devlink/ \fIi\fR .BI /dev/aoe/ n.m /ident \&... .fi .SH DESCRIPTION .PP The AoE (ATA-over-Ethernet) interface serves a three-level directory providing control and access to AoE targets. The interface provided is primarily intended for low-level control of the AoE initiator. See .IR sdaoe (3) for the standard interface. .PP In order to access AoE targets, one or more Ethernet controllers need to be bound to the AoE initiator. By default, the system starts with no interfaces bound. For automatic binding of interfaces on boot, the .B aoeif configuration variable is used in .IR plan9.ini (8). Ethernet interfaces are specified as .BI ether n not as .BI #l n \fR.\fI To bind the first and second Ethernet devices on boot, add .IP .EX aoeif=ether0 ether1 .EE .PP To bind ether1 to a running system: .IP .EX % echo bind '#l1/ether1' > /dev/aoe/ctl .EE .PP And to unbind it .IP .EX % echo unbind '#l1/ether1' > /dev/aoe/ctl .EE .PP When an interfaces are unbound, targets depending on that interface are removed. .PP Each local interface is called a netlink. The mapping of AoE targets to netlinks is called a devlink. Each devlink may see multiple interfaces per target. For example, if the local machine has one Ethernet address bound and the target has two interfaces on the same Ethernet segment, this will result in one netlink and one devlink with two Ethernet addresses. AoE frames are sent in round-robin fashion. Each successive frame is sent on the next address available on the next available devlink (local interface). .PP Normally the initiator automatically discovers and adds new device directories on startup. New devices are not added except as new interfaces are bound to the initiator. There are several messages that can be sent to the .B ctl file which alter this behavior: .TP .BI autodiscover\ toggle If toggle is .IR nil , the state of .B autodiscover is toggled. If it is the string .BR on , it is turned on. Any other string turns .B autodisover off. This option is not useful after Ethernet devices have been bound. .TP .BI discover\ shelf.slot Attempt to find the named target all bound interfaces. .TP .BI remove\ shelf.slot The converse of .BR discover. Remove the named target if it exists. .TP .BI rediscover\ toggle Allow or disallow rediscovery. This allows for automatic discovery of new targets. Unfortunately, it also allows automatic modification or loss of existing targets. This option is considered dangerous. .PP Reading the ctl file returns a list of colon-separated lines .TP .B debug .TP .B autodiscover .TP .B rediscover Returns the current state of the named variable. Writing the variable's name to the control file toggles the state of that variable. .TP .BI if n\ \fLpath Path to \fInth\fR bound Ethernet device. .TP .BI if n\ \fLea Ethernet address of this device. .TP .BI if n\ \fLflag ``Up'' indicates this interface is available. .TP .BI if n\ \fLlostjumbo Number of consecutive lost jumbograms. .TP .BI if n\ \fLdatamtu Incorrect and unused. .PP Once configured, each AoE target is accessed via files in the directory named for its shelf and slot. For example, shelf 42, slot 0 would be accessed through the path .LR /dev/aoe/42.0 . The .B ident file contains the read-only, verbatim result of the identify unit ATA command. The .B config file contains the target's AoE configuration string. Writing to this file sets the targets configuration string. .PP Reading the .B ctl file returns a list of colon-separated lines: .TP .B state ``Up'' or ``down''. .TP .B nopen Number of clients using this target. .TP .B nout Number of outstanding AoE frames. .TP .B nmaxout Maximum number of outstanding frames allowed. .TP .B nframes Maximum number of outstand frames. .B Nframes is greater than .B nmaxout when the initiator is reducing the number of in-flight frames due to packet loss. It is assumed that packet loss is due to an overwhelmed target and not poor network conditions. .TP .BI maxbcount Maximum number of data bytes per AoE frame. Using standard frames, .B maxbcount is 1024 or two sectors. AoE ATA headers are 36 bytes. .TP .B model .TP .B serial .TP .B firmware The respective fields from the ATA .B identify unit command. .TP .B flag List of flags useful for debugging. The flag .B jumbo indicates that jumbo frames are accepted, not that they are being used. .B Maxbcount should be consulted for this purpose. .PP The .B data file may be read or written like a normal file. Reads and writes to this file are sent as AoE commands to the target. The size of this file is the usable size of the target. .PP The .B devlink directory contains one file for each interface the target was discovered on. The files are numbers from 0 to .I n and contain a list of colon-separated lines: .TP .B addr A space-seperated list of the target's Ethernet addresses visible from this interface. .TP .B npkt The number of frames sent on this interface. .TP .B resent The number of frames resent. Frames are resent when they have been outstanding twice the RTT average. .TP .B flag ``Up'' when the netlink is up. .TP .B rttavg .B mintimer Minimum timer and RTT average as per .IR "Congestion Avoidance and Control" . .TP .B nl path Path of the Ethernet device. .TP .B nl ea Ethernet address of the local Ethernet device. .TP .B nl flag ``Up'' if the local interface is up. .TP .B nl lostjumbo Number of consecutive jumbograms lost. .TP .B nl datamtu Unused. .PP .SH SOURCE .B /sys/src/9/port/devaoe.c .SH SEE ALSO .IR cec (1), .IR snoopy (8), .IR sd (3), .IR sdaoe (3), .IR vblade (1), .br .BR http://www.coraid.com/documents/AoEr10.txt , .br Van Jacobson and Michael J. Karels, .IR "``Congestion Avoidance and Control''" , ACM Computer Communication Review; Proceedings of the Sigcomm '88 Symposium in Stanford, CA, August, 1988. .SH BUGS There is no .B raw file for executing arbitrary commands.