Multipath Configuration

sudo systemctl enable --now multipathd

sudo tee /etc/multipath.conf > /dev/null <<'EOF'
defaults {
    user_friendly_names     yes
    find_multipaths         no
    enable_foreign          "^$"
    polling_interval        10
    path_selector           "service-time 0"
    path_grouping_policy    group_by_prio
    failback                immediate
    no_path_retry           0
}

blacklist {
    devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st|nvme)[0-9]*"
    devnode "^hd[a-z]"
    devnode "^sd[a]$"
    devnode "^vd[a-z]"
}

# Add device-specific settings for your storage array
# Consult your storage vendor documentation for recommended values
#devices {
#    device {
#        vendor               "VENDOR"
#        product              "PRODUCT"
#        path_selector        "service-time 0"
#        hardware_handler     "1 alua"
#        path_grouping_policy group_by_prio
#        prio                 alua
#        failback             immediate
#        path_checker         tur
#        fast_io_fail_tmo     5
#        dev_loss_tmo         60
#        no_path_retry        0
#    }
#}
EOF

sudo systemctl restart multipathd
sudo multipath -ll

# Show multipath topology - expect 4 paths (2 HBA ports  2 array controllers)
sudo multipath -ll

# Example output:
# mpatha (3624a937...) dm-0 PURE,FlashArray
# size=1.0T features='0' hwhandler='1 alua' wp=rw
# |-+- policy='service-time 0' prio=50 status=active
# | |- 6:0:0:1 sdb 8:16 active ready running
# | `- 7:0:0:1 sdd 8:48 active ready running
# `-+- policy='service-time 0' prio=10 status=enabled
#   |- 6:0:0:1 sdc 8:32 active ready running
#   `- 7:0:0:1 sde 8:64 active ready running

sudo journalctl -u multipathd -n 50