Disabling Oracle Solaris Multipathing Software (MPXIO/scsi_vhci) on Internal SAS (Single Path) Disks under ZFS rpool Mirror

(Doc ID 2167120.1)

Last updated on AUGUST 10, 2016

Applies to:

Solaris Operating System - Version 10 3/05 to 11.3 [Release 10.0 to 11.0]
Information in this document applies to any platform.

Goal

How to safely disable multipathing for internal disks in an Oracle Server (except in some LDom configurations, see below)

The majority of Oracle servers have one physical path to their internal disks.

While use of multipathing software such as Oracle Solaris MPxIO is strongly recommended (and configured at the factory), UNLESS your system is an Oracle Engineered System (including SuperCluster) it is not mandatory to use MPxIO on internal disks.

Some customers may wish to disable MPxIO for internal single-path devices.

Regardless of whether Oracle Solaris MPxIO or a competing multipath solution is used, each device in a host should only ever be accessed by ONE multipath solution.

Disabling Oracle Solaris MPxIO for either internal devices will not affect Oracle Solaris ZFS' ability to access those devices unless there is a disk fault. Oracle Solaris ZFS and MPxIO use the same device identification method.

 

Important notice when disks are under LDom configuration

The modification of device names may create serious follow-up problems on a primary domain which exports internal SAS-disks to Guest LDoms as vdisks

LDom config might break in case customer exported one-or-more of the internal disks as vdisks to LDom Guest.

LDom is not able to migrate the vdsdev automatically. The conversion of the vdsdev-mapping MPxIO names to physical path names must be performed manually with great care in order to avoid confusion and/or data corruption.

In this scenario, please contact with Oracle support and check with LDom group for the steps to follow.

 

Solution

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