Configure DM Multipath (RHEL 6.2+) and udev rules (RHEL 6.x, 7.x) for Pure Storage

config_for_pure.sh

#!/bin/bash

# Create default multipath.conf
[[ -f "/etc/multipath.conf" ]] && read -r -p "/etc/multipath.conf exists.  Continue? [y/N] " response
if [[ "$response" =~ ^(no|n)$ ]]; then
    echo "Quitting."
    exit 1
else
    echo "Writing /etc/multipath.conf"

    cat << EOF > "/etc/multipath.conf"
defaults {
    find_multipaths     yes
    polling_interval    10
    user_friendly_names no
}

devices {
    device {
        vendor                "PURE"
        path_selector         "queue-length 0"
        path_grouping_policy  multibus
        path_checker          tur
        fast_io_fail_tmo      10
        dev_loss_tmo          60
        no_path_retry         0
    }
}
blacklist {
    device {
        vendor  "LSI"
        product ".*"
    }
    devnode "^emcpower[a-z]"
    device {
        vendor  "EMC"
        product ".*"
    }
    device {
        vendor  "DGC"
        product ".*"
    }
}
EOF
fi

# Create udev rules for Pure storage
[[ -f "/etc/udev/rules.d/99-pure-storage.rules" ]] && read -r -p "/etc/udev/rules.d/99-pure-storage.rules exists.  Continue? [y/N] " response
if [[ "$response" =~ ^(no|n)$ ]]; then
    echo "Quitting."
    exit 1
else
    echo "Creating /etc/udev/rules.d/99-pure-storage.rules"

    cat << EOF > "/etc/udev/rules.d/99-pure-storage.rules"
# Recommended settings for Pure Storage FlashArray.

# Use noop scheduler for high-performance solid-state storage
ACTION=="add|change", KERNEL=="sd*[!0-9]", SUBSYSTEM=="block", ENV{ID_VENDOR}=="PURE", ATTR{queue/scheduler}="noop"

# Reduce CPU overhead due to entropy collection
ACTION=="add|change", KERNEL=="sd*[!0-9]", SUBSYSTEM=="block", ENV{ID_VENDOR}=="PURE", ATTR{queue/add_random}="0"

# Spread CPU load by redirecting completions to originating CPU
ACTION=="add|change", KERNEL=="sd*[!0-9]", SUBSYSTEM=="block", ENV{ID_VENDOR}=="PURE", ATTR{queue/rq_affinity}="2"

# Set the HBA timeout to 60 seconds
ACTION=="add", SUBSYSTEMS=="scsi", ATTRS{model}=="FlashArray      ", RUN+="/bin/sh -c 'echo 60 > /sys/\$DEVPATH/device/timeout'"
EOF
fi