Dell Acceleration Appliances for Databases - Manual (Page 55)

Configuring Multipathing on Linux
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INSTALLING MPIO ON LINUX
The basic components for Linux multipathing are described below.
•
dm_multipath
kernel module – Reroutes I/O, supports failover for paths & path groups.
•
mpathconf
utility – Configures and enables device mapper multipathing
•
multipath
command – Lists & configures multipath devices. Start with
/etc/rc.sysinit
, or
udev
when a block device is added.
•
multipathd
daemon – Monitors paths; as paths fail and come back, it may initiate path
group switches. Provides for interactive changes to multipath devices. This must be restarted
for any changes to the
/etc/multipath.conf
file
•
kpartx
command - Creates device mapper devices for the partitions on a device.
Use this command for DOS-based partitions with DM-MP. The
kpartx
is provided in its own
package, but the device mapper-multipath package depends on it.
The basic steps for installing DM Multipath are listed here:
1. Install
device-mapper-multipath RPM
.
2. On OL 6.4 or RHEL, run
mpathconf --enable
to enable multipathing.
3. If necessary, edit the
multipath.conf
configuration file to modify default values and save
the updated file.
4. Start the multipath daemon.
Common mpathconf Settings
Here are some common multipathing configuration settings:
mpathconf --find_multipaths y
mpathconf --with_module y
mpathconf --with_chkconfig
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