eecdf22672
The old area has a new URL. Also, now that the driver can perform better, it is worth mentioning the VM settings that help aoe to sink dirty pages out early, avoiding unecessary memory pressure when much I/O is going on. Signed-off-by: Ed Cashin <ecashin@coraid.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
127 lines
4.6 KiB
Plaintext
127 lines
4.6 KiB
Plaintext
The EtherDrive (R) HOWTO for 2.6 and 3.x kernels is found at ...
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http://support.coraid.com/support/linux/EtherDrive-2.6-HOWTO.html
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It has many tips and hints! Please see, especially, recommended
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tunings for virtual memory:
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http://support.coraid.com/support/linux/EtherDrive-2.6-HOWTO-5.html#ss5.19
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The aoetools are userland programs that are designed to work with this
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driver. The aoetools are on sourceforge.
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http://aoetools.sourceforge.net/
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The scripts in this Documentation/aoe directory are intended to
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document the use of the driver and are not necessary if you install
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the aoetools.
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CREATING DEVICE NODES
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Users of udev should find the block device nodes created
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automatically, but to create all the necessary device nodes, use the
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udev configuration rules provided in udev.txt (in this directory).
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There is a udev-install.sh script that shows how to install these
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rules on your system.
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If you are not using udev, two scripts are provided in
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Documentation/aoe as examples of static device node creation for
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using the aoe driver.
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rm -rf /dev/etherd
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sh Documentation/aoe/mkdevs.sh /dev/etherd
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... or to make just one shelf's worth of block device nodes ...
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sh Documentation/aoe/mkshelf.sh /dev/etherd 0
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There is also an autoload script that shows how to edit
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/etc/modprobe.d/aoe.conf to ensure that the aoe module is loaded when
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necessary.
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USING DEVICE NODES
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"cat /dev/etherd/err" blocks, waiting for error diagnostic output,
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like any retransmitted packets.
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"echo eth2 eth4 > /dev/etherd/interfaces" tells the aoe driver to
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limit ATA over Ethernet traffic to eth2 and eth4. AoE traffic from
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untrusted networks should be ignored as a matter of security. See
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also the aoe_iflist driver option described below.
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"echo > /dev/etherd/discover" tells the driver to find out what AoE
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devices are available.
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These character devices may disappear and be replaced by sysfs
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counterparts. Using the commands in aoetools insulates users from
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these implementation details.
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The block devices are named like this:
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e{shelf}.{slot}
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e{shelf}.{slot}p{part}
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... so that "e0.2" is the third blade from the left (slot 2) in the
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first shelf (shelf address zero). That's the whole disk. The first
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partition on that disk would be "e0.2p1".
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USING SYSFS
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Each aoe block device in /sys/block has the extra attributes of
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state, mac, and netif. The state attribute is "up" when the device
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is ready for I/O and "down" if detected but unusable. The
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"down,closewait" state shows that the device is still open and
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cannot come up again until it has been closed.
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The mac attribute is the ethernet address of the remote AoE device.
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The netif attribute is the network interface on the localhost
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through which we are communicating with the remote AoE device.
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There is a script in this directory that formats this information
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in a convenient way. Users with aoetools can use the aoe-stat
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command.
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root@makki root# sh Documentation/aoe/status.sh
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e10.0 eth3 up
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e10.1 eth3 up
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e10.2 eth3 up
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e10.3 eth3 up
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e10.4 eth3 up
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e10.5 eth3 up
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e10.6 eth3 up
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e10.7 eth3 up
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e10.8 eth3 up
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e10.9 eth3 up
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e4.0 eth1 up
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e4.1 eth1 up
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e4.2 eth1 up
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e4.3 eth1 up
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e4.4 eth1 up
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e4.5 eth1 up
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e4.6 eth1 up
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e4.7 eth1 up
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e4.8 eth1 up
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e4.9 eth1 up
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Use /sys/module/aoe/parameters/aoe_iflist (or better, the driver
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option discussed below) instead of /dev/etherd/interfaces to limit
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AoE traffic to the network interfaces in the given
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whitespace-separated list. Unlike the old character device, the
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sysfs entry can be read from as well as written to.
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It's helpful to trigger discovery after setting the list of allowed
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interfaces. The aoetools package provides an aoe-discover script
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for this purpose. You can also directly use the
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/dev/etherd/discover special file described above.
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DRIVER OPTIONS
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There is a boot option for the built-in aoe driver and a
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corresponding module parameter, aoe_iflist. Without this option,
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all network interfaces may be used for ATA over Ethernet. Here is a
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usage example for the module parameter.
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modprobe aoe_iflist="eth1 eth3"
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