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5.8 Configuring Multipathing for an Existing
Software RAID
Ideally, you should configure multipathing for devices before you use them as components of a
software RAID device. If you add multipathing after creating any software RAID devices, the
Multipath service might be starting after the MD service on reboot, which makes multipathing appear
not to be available for RAIDs. You can use the procedure in this section to get multipathing running
for a previously existing software RAID.
For example, you might need to configure multipathing for devices in a software RAID under the
following circumstances:
NOTE: The following instructions assume the software RAID device is /dev/md0, which is its
device name as recognized by the kernel. Make sure to modify the instructions for the device name
of your software RAID.
1 Open a terminal console, then log in as the root user or equivalent.
2 If any software RAID devices are currently mounted or running, enter the following commands
3 Stop the boot.md service by entering
4 Start the boot.multipath and multipathd services by entering the following
5 After the multipathing services are started, verify that the software RAID's component devices
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SLES 10 Storage Administration Guide for EVMS
If you create a new software RAID as part of the Partitioning settings during a new install or
upgrade.
If you did not configure the devices for multipathing before using them in the software RAID
as a member device or spare.
If you grow your system by adding new HBA adapters to the server or expanding the storage
subsystem in your SAN.
Except where otherwise directed, use this console to enter the commands in the following
steps.
for each device to dismount the device and stop it.
umount /dev/md0
mdadm --misc --stop /dev/md0
/etc/init.d/boot.md stop
commands:
/etc/init.d/boot.multipath start
/etc/init.s/multipathd start
are listed in the /dev/disk/by-id directory. Do one of the following:
Devices Are Listed: The device names should now have symbolic links to their Device
Mapper device names, such as dev/dm-1.
Devices Are Not Listed: Force the multipath service to recognize them by flushing
and rediscovering the devices.
To do this, enter the following commands:
multipath -F
multipath -v0
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