Multipath

https://en.wikipedia.org/wiki/Linux_DM_Multipath

• multipath -l
• multipath -t

-t Display the currently used multipathd configuration

• multipathd show config

• Ubuntu: multipath-tools package
  • Binaries: multipath multipathd mpathpersist
• RHEL: device-mapper-multipath package

Config files:

• /etc/multipath.confhttps://manpages.debian.org/unstable/multipath-tools/multipath.conf.5.en.html
• /etc/multipath/wwids

Default multipath.conf configuration

RHEL
cat /etc/multipath.conf | grep -v "#" | grep .
defaults {
    polling_interval            5
    no_path_retry               4
    user_friendly_names         no
    flush_on_last_del           yes
    fast_io_fail_tmo            5
    dev_loss_tmo                30
    max_fds                     4096
}
blacklist {
        protocol "(scsi:adt|scsi:sbp)"
}
devices {
    device {
        all_devs                yes
        no_path_retry           4
    }
}

See also

• EMC powerpath
• Fibre Channel: SAN, HBA, LUN, WWN, WWPN, LIF, rescan-scsi-bus.sh

https://www.thegeekdiary.com/understanding-the-dm-multipath-configuration-file-etc-multipath-conf/