Technical data

4 Using HPDM Multipath
This chapter addresses the following topics:
• Creating an Alias using /etc/multipath.conf file
• Using Multipath Map
• Supporting Clustering Solutions
Creating an Al
ias using /etc/multipath.conf file
This section d
escribes var ious par ameters available for updating /etc/multipath.conf file.
The multipa th devices are cre ated in the /dev/mapper directoryinthehosts.Thesedevicesaresimilar
to any other block devices present in the host, and are used for any block or file level I/O operations,
such as creat
ing the file system.
Youmustusethedevicesunder/dev/mapper/ .Youcancreateanewdevicealiasbyusing
the alias and the WWID attributes of the multipath d evice present in the multipath s ubsection of
the/etc/mutipath.conf file.
Exam ple 2. U
pdating /etc/multipath.conf file
For example
, when the following subsection is added in the /etc/multipath.conf file for the LUN
with WWID 3600508b30090f5d0d2a9d64590490022, a multipath device, mydatadisk1,is
created under /dev/mapper:
multipaths
{
multipath
{
wwid
alias
path_group
ing_policy
path_check
er
path_selec
tor
3600508b30
090f5d0d2a9d64590490022
mydatadisk
1
multibus
tur
"round-rob
in 0"
}
}
You can use
/dev/mapper/mydatadisk1 like any other block device.
Using Multipath Map
This section describes a multipath map obtained by executing the multipath–ll command, based on a
sample multipath.conf file.
Following is a sample multipath.conf file (for RHEL4) with parameters to support EVA 4000 as a
storage controller:
defaults
{
Device Mapper Multipath Enablement Kit for HP StorageWorks Disk Arrays
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