Knowledge Base

How to configure multipath for EqualLogic storage array PS6110


Applies To:

Oracle Database Oracle 12cR1 12.1.0.1.0 Enterprise Edition

Operating System(s) Red Hat Enterprise Linux with kernel 2.6.32-431.el6.x86_64

Storage EqualLogic Storage Array PS6110

Problem:

How to configure multipath for EqualLogic Storage Array PS6110?

Solution:

Device mapper multipath utility is used to achieve consistent naming of shared volumes across all nodes in a RAC set up.

The four components of a multipath configuration file are:
  • blacklist
  • blacklist exceptions
  • defaults &
  • multipaths
The wiki article How to configure device-mapper-multipath provides the steps involved in configuring the /etc/multipath.conf file. However for the purpose of deploying the Oracle RAC12cR1 on RHEL 6.5, with EqualLogic PS6110 as the storage, the defaults section of the multipath configuration file needs to have the values given below:
defaults {

udev_dir /dev

polling_interval 10

path_selector "round-robin 0"

path_grouping_policy multibus

getuid_callout "/lib/udev/scsi_id --whitelisted --device=/dev/%n"

prio alua

path_checker tur

rr_min_io 100

max_fds 8192

rr_weight priorities

failback immediate

no_path_retry fail

user_friendly_names yes

}

Of particular interest is the path checker attribute which specifies the default method used to determine the state of the paths. If it is set to read sector0 it reads the first sector of the device. When set to a value of "tur" Test Unit Ready, it issues a TUR to the device. For Equallogic PS 6110 the path checker attribute needs to be set to "tur".


Article ID: SLN310927

Last Date Modified: 08/16/2018 07:15 AM


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