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LinuxSCSI
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#!/bin/sh
#
#
# LinuxSCSI
#
# Description: Enables/Disables SCSI devices to protect them from being
# used by mistake
#
#
# Author: Alan Robertson
# Support: linux-ha@lists.linux-ha.org
# License: GNU General Public License (GPL)
# Copyright: (C) 2002 - 2005 IBM
#
# CAVEATS: See the usage message for some important warnings
#
# usage: ./LinuxSCSI (start|stop|status|monitor|meta-data|validate-all|methods)
#
# OCF parameters are as below:
# OCF_RESKEY_scsi
#
# An example usage in /etc/ha.d/haresources:
# node1 10.0.0.170 LinuxSCSI:0:0:11
#
#######################################################################
# Initialization:
. ${OCF_ROOT}/resource.d/heartbeat/.ocf-shellfuncs
#######################################################################
zeropat="[ 0]0"
PROCSCSI=/proc/scsi/scsi
usage() {
cat <<-!
usage: $0 (start|stop|status|monitor|meta-data|validate-all|methods)
$0 manages the availability of a SCSI device from the point
of view of the linux kernel. It make Linux believe the
device has gone away, and it can make it come back again.
The purpose of this resource script is to keep admins from
accidentally messing with a shared disk that is managed by the
HA subsystem and is currently owned by the other side.
To get maximum benefit from this feature, you should (manually)
disable the resources on boot, and let your HA software enable
them when it wants to acquire the disk.
The kernel code says this is potentially dangerous. DO NOT USE
IT ON AN ACTIVE DEVICE. If the device is inactive, this script
will make it stay inactive, when given "off". If you inactivate
the wrong device, you may have to reboot your machine, and your
data may take a hit.
On the other hand, at least one RAID controller requires the
use of this technique for it to work correctly in a failover
environment - so it is believed that it is more stable in this
usage than the comments in the code imply.
Here are the warnings from the kernel source about the "stop"
operation as of 2.4.10:
------------------------------
Consider this feature pre-BETA.
CAUTION: This is not for hotplugging your peripherals. As
SCSI was not designed for this, you could damage your
hardware and thoroughly confuse the SCSI subsystem.
Similar warnings apply to the "start" operation...
Consider this feature BETA.
CAUTION: This is not for hotplugging your peripherals.
As SCSI was not designed for this you could damage your
hardware !
However perhaps it is legal to switch on an already connected
device. It is perhaps not guaranteed this device doesn't corrupt
an ongoing data transfer.
-------------------------
So, Caveat Emptor, and test this feature thoroughly on
your kernel and your configuration with real load on the SCSI
bus before using it in production!
Another potential trouble spot...
The order in which you bring up LinuxSCSI resources determines which
SCSI device they show up as on Linux. If you have two SCSI devices
in different resource groups they will be brought up asyncronously
resulting in indeterminate device name assignments. This usually
happens in an active-active configuration.
To solve this you probably should use LVM or EVMS to manage these
volumes. LVM and EVMS solve this problem for you by labels they
keep in the volumes. If you don't use a reasonable volume manager,
then you'll have to mount by UUID.
!
}
meta_data() {
cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="LinuxSCSI">
<version>1.0</version>
<longdesc lang="en">
This is a resource agent for LinuxSCSI. It manages the availability of a
SCSI device from the point of view of the linux kernel. It make Linux
believe the device has gone away, and it can make it come back again.
</longdesc>
<shortdesc lang="en">LinuxSCSI resource agent</shortdesc>
<parameters>
<parameter name="scsi" unique="0" required="1">
<longdesc lang="en">
The SCSI instance to be managed.
</longdesc>
<shortdesc lang="en">SCSI instance</shortdesc>
<content type="string" default="" />
</parameter>
</parameters>
<actions>
<action name="start" timeout="10" />
<action name="stop" timeout="10" />
<action name="methods" timeout="5" />
<action name="status" depth="0" timeout="10" interval="10" start-delay="10" />
<action name="monitor" depth="0" timeout="10" interval="10" start-delay="10" />
<action name="meta-data" timeout="5" />
<action name="validate-all" timeout="5" />
</actions>
</resource-agent>
END
}
scsi_methods() {
cat <<-!
start
stop
status
monitor
validate-all
methods
!
}
parseinst() {
lun=0
case "$1" in
[0-9]*:[0-9]*:[0-9]*);;
[0-9]*:[0-9]*:[0-9]*:[0-9]*)
lun=`echo "$1" | cut -d: -f4`;;
*) #host=error
#channel=error
#target=error
#lun=error
ocf_log err "Invalid SCSI instance $1"
exit $OCF_ERR_ARGS
esac
host=`echo "$1" | cut -d: -f1`
channel=`echo "$1" | cut -d: -f2`
target=`echo "$1" | cut -d: -f3`
}
#
# start: Enable the given SCSI device in the kernel
#
scsi_start() {
parseinst "$1"
# [ $target = error ] && exit 1
# echo "scsi-add-single-device $host $channel $target $lun" >>$PROCSCSI
echo "scsi add-single-device $host $channel $target $lun" >>$PROCSCSI
if
scsi_status "$1"
then
return $OCF_SUCCESS
else
ocf_log err "SCSI device $1 not active!"
return $OCF_ERR_GENERIC
fi
}
#
# stop: Disable the given SCSI device in the kernel
#
scsi_stop() {
parseinst "$1"
# [ $target = error ] && exit 1
echo "scsi remove-single-device $host $channel $target $lun" >>$PROCSCSI
if
scsi_status "$1"
then
ocf_log err "SCSI device $1 still active!"
return $OCF_ERR_GENERIC
else
return $OCF_SUCCESS
fi
}
#
# status: is the given device now available?
#
scsi_status() {
parseinst "$1"
# [ $target = error ] && exit 1
[ $channel -eq 0 ] && channel=$zeropat
[ $target -eq 0 ] && target=$zeropat
[ $lun -eq 0 ] && lun=$zeropat
greppat="Host: *scsi$host *Channel: *$channel *Id: *$target *Lun: *$lun"
grep -i "$greppat" $PROCSCSI >/dev/null
if [ $? -eq 0 ]; then
return $OCF_SUCCESS
else
return $OCF_NOT_RUNNING
fi
}
#
# validate_all: Check the OCF instance parameters
#
scsi_validate_all() {
parseinst $instance
return $OCF_SUCCESS
}
if
( [ $# -ne 1 ] )
then
ocf_log err "Parameter number error."
usage
exit $OCF_ERR_GENERIC
fi
#if
# [ -z "$OCF_RESKEY_scsi" ] && [ "X$1" = "Xmethods" ]
#then
# scsi_methods
# exit #?
#fi
case $1 in
methods) scsi_methods
exit $OCF_SUCCESS
;;
meta-data) meta_data
exit $OCF_SUCCESS
;;
usage) usage
exit $OCF_SUCCESS
;;
*) ;;
esac
if
[ -z "$OCF_RESKEY_scsi" ]
then
ocf_log err "You have to set a valid scsi id at least!"
# usage
exit $OCF_ERR_GENERIC
fi
instance=$OCF_RESKEY_scsi
case $1 in
start) scsi_start $instance
;;
stop) scsi_stop $instance
;;
status|monitor)
if
scsi_status $instance
then
ocf_log info "SCSI device $instance is running"
return $OCF_SUCCESS
else
ocf_log info "SCSI device $instance is stopped"
exit $OCF_NOT_RUNNING
fi
;;
validate-all) scsi_validate_all
;;
*) usage
exit $OCF_ERR_UNIMPLEMENTED
;;
esac
exit $?
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Sat, Jan 25, 6:38 AM (1 d, 7 h)
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LinuxSCSI (7 KB)
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