Dell PowerVault MD3200i - Manual (Page 198)

196 Configuration: Device Mapper Multipath for Linux
2 Stop the Device Mapper multipath service
# /etc/init.d/multipathd stop
3 Flush the Device Mapper multipath maps list to remove any old or
modified mappings
# multipath –F
NOTE: The boot operating system drive may have an entry with the Device
Mapper multipathing table. This is not affected by the multipath –F
command. However, using #multipath –ll must not show any
multipathing devices with model “MD3200i” or “MD3200i”.
4 Log out of all iSCSI sessions from the host server to the storage array
# iscsiadm –m node --logout
Important Information About Special Partitions
When using Device Mapper with the MD3200i Series array, all physical disks
are assigned a disk device node. This includes a special device type used for
in-band management of the MD3200i Series array, known as the Access Disk
or Universal Xport device.
CAUTION: Certain commands, such as lsscsi, displays one or more instances of
Universal Xport devices. These device nodes must never be accessed, mounted, or
used in any way. Doing so could cause loss of communication to the storage array
and possibly cause serious damage to the storage array, potential making data
stored on the array inaccessible.
Only multipathing device nodes and partition nodes created using the
directions provided above must be mounted or in any way accessed by the
host system or its users.
Table 14-1. Useful Device Mapper Commands
Command Descriptions
multipath –h Prints usage information
multipath –ll Displays the current multipath topology using all available
information (sysfs, the device mapper, path checkers, and
so on)
multipath Re-aggregates multipathing device with simplified output.
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