Red Hat DEVICE-MAPPER MULTIPATH 5.2 Uživatelský manuál stáhnout pdf (Strana 18)

DotHill – Linux Device Mapper Multipath “How To” for Storage Revision 4

You must configure HBA parameters for the Device Mapper Multipath. The HBA time-out val-

ues are typically set for non-DM-MP environments, where longer time outs are necessary. This

is because the only alternative is to send an error to the application. However, with DM-MP,

errors like cable failures must be reported earlier so that the multipath layer can quickly take

action and redirect the I/O to another path.

This section describes how to configure the host bus adapter driver:

7.1 Configuring QLogic HBA parameters

To configure QLogic HBA parameter, complete the following steps:

1. For QLogic 2xxx family of HBAs, add the following line to the

/etc/modprobe.conf file:

options qla2xxx qlport_down_retry=l ql2xretrycount=5 ql2xfailover=0

2. Rebuild the initrd file using the mkinitrd command. A sample command is show below.

For more information see MKINITRD(8).

# mkinitrd /boot/initrd-2.6.9-34ELsmp-dmmpparams 2.6.9-34.ELsmp

3. Edit your boot loader configuration file to make your new initrd file available and reboot the

host.

7.2 Configuring QLogic/Emulex HBAs for R/Evolution storage

Please refer to the REvo 2730 Interoperability Matrix and Revolution Storage System Best

Practices Guide (part number 83-00004171) for setting HBA parameters for use against the

R/Evo storage. These documents are available in the Dot Hill Web site

(www.dothill.com/support).

8 Managing DM-MP Devices

Initial configuration of multipath devices is done by the multipath.conf file. However, the

command line tool provides a way to make modifications to their attributes as well as monitor

them. Table 2 lists the basic options supported by the multipath CLI utility.

Table 2: Basic Command of Device Mapper Multipath CLI

Command Description

multipath

Create DM-MP devices

multipath -d

Display potential paths but do not create any devices

multipath -F

Delete all DM-MP devices

multipath -l [device]

Display the current multipath topology from sysfs and

device mapper

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Red Hat DEVICE-MAPPER MULTIPATH 5.2 Uživatelský manuál Strana 18