Installation guide

Enterprise Linux 4 in Update 2 and into Novell SUSE Linux Enterprise Server 9 in Service Pack 2. To setup

multipathing on Linux:

Procedure

1. Edit the /etc/multipath.conf file:

○ Comment out the following lines at the top of the file. This section of the configuration file, in its initial

state, blacklists all devices. You must comment it out to enable multipathing:

blacklist {

devnode "*"

}

○ Add configuration information. For example:

multipath {

wwid 360060e80056fb70000006fb700000816

alias TEST_DATA

path_grouping_policy failover

mode 660

uid 8205

gid 471

}

2. Run these commands:

# modprobe dm-multipath – add multipathing module to Linux kernel

# modprobe dm-round-robin – add multipathing round-robin module to Linux kernel

# /etc/init.d/multipathd start – start multipath service

# multipath – automatically detect multiple paths to devices and configure

multipathing

# chkconfig multipathd on – turn on multipath service

# multipath –l – displays all paths to devices

The /dev/mapper/mpath<N> devices are persistent and they are created early in the boot process. Use

these device names to access the multipathed devices.

For example:

○ /usr2/sybase/ASE1503/dev/wdb_data – is a symbolic link pointing to /dev/raw/raw73.

○ /dev/raw/raw73 – is a raw character device mapped to /dev/mapper/mp_wdb_data.

○ /dev/mapper/mp_wdb_data – is a multipath device that contains two paths: /dev/sdbf

and /dev/sds.

○ /dev/sdbf – is a block device that corresponds to SCSI generic raw character device /dev/

sg61.

○ /dev/sds – is a block device that corresponds to SCSI generic raw character device /dev/

sg20.

Installation Guide for Linux

Planning Your SAP ASE Installation