Multipath with storage

1.install multipath tools
#apt-get install multipath-tools  multipath-tools-boot

2. create multipath.conf
#cp /usr/share/doc/multipath-tools/examples/multipath.conf.synthetic /etc/multipath.conf

3.modify mutipath.conf
#vim /etc/multipath.conf

defaults {
        path_grouping_policy    multibus
        failback                immediate
        no_path_retry           fail
        user_friendly_names     yes
}
blacklist {
        devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
        devnode "^hd[a-z][[0-9]*]"
        devnode "^cciss!c[0-9]d[0-9]*[p[0-9]*]"

      }

blacklist define device not included by multipath

4.restart multipath service

#service multipath-tools restart

5.show multipath status

#multipath -ll

mpath0 (360050cc000203d7a0000000000000008) dm-0 OVERLAND,RAID 1200

[size=1.5T][features=0][hwhandler=0]

\_ round-robin 0 [prio=2][active]

 \_ 2:0:0:0 sda 8:0   [active][ready]

 \_ 2:0:1:0 sdb 8:16  [active][ready]

6. if your disk is GPT format then install fixparts and install deb 

#wget http://download.opensuse.org/repositories/home:/srs5694/xUbuntu_10.04/amd64/gptfdisk_0.8.8-1_amd64.de

#dpkg -i gptfdisk_0.8.8-1_amd64.deb

#apt-get -f install

7. format gpt disk 

# fixparts /dev/mapper/mpath0