How can I monitor the TBW on my Samsung SSD?

FULL DISCLOSURE: The scipt/commands present in this answer are not my own, but rather the work of J. D. G. Leaver. They were sourced from a blog post on his website.

NB:

  • This will only report accurate numbers for Samsung SSDs
  • You need to have smartctl installed

Method 1:

Here's a handy little script that will allow you to monitor the TBW of your SSD, along with some other information:

#!/bin/bash

#######################################
# Variables                           #
#######################################

SSD_DEVICE="/dev/sda"

ON_TIME_TAG="Power_On_Hours"
WEAR_COUNT_TAG="Wear_Leveling_Count"
LBAS_WRITTEN_TAG="Total_LBAs_Written"
LBA_SIZE=512 # Value in bytes

BYTES_PER_MB=1048576
BYTES_PER_GB=1073741824
BYTES_PER_TB=1099511627776

#######################################
# Get total data written...           #
#######################################

# Get SMART attributes
SMART_INFO=$(sudo /usr/sbin/smartctl -A "$SSD_DEVICE")

# Extract required attributes
ON_TIME=$(echo "$SMART_INFO" | grep "$ON_TIME_TAG" | awk '{print $10}')
WEAR_COUNT=$(echo "$SMART_INFO" | grep "$WEAR_COUNT_TAG" | awk '{print $4}' | sed 's/^0*//')
LBAS_WRITTEN=$(echo "$SMART_INFO" | grep "$LBAS_WRITTEN_TAG" | awk '{print $10}')

# Convert LBAs -> bytes
BYTES_WRITTEN=$(echo "$LBAS_WRITTEN * $LBA_SIZE" | bc)
MB_WRITTEN=$(echo "scale=3; $BYTES_WRITTEN / $BYTES_PER_MB" | bc)
GB_WRITTEN=$(echo "scale=3; $BYTES_WRITTEN / $BYTES_PER_GB" | bc)
TB_WRITTEN=$(echo "scale=3; $BYTES_WRITTEN / $BYTES_PER_TB" | bc)

# Output results...
echo "------------------------------"
echo " SSD Status:   $SSD_DEVICE"
echo "------------------------------"
echo " On time:      $(echo $ON_TIME | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta') hr"
echo "------------------------------"
echo " Data written:"
echo "           MB: $(echo $MB_WRITTEN | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta')"
echo "           GB: $(echo $GB_WRITTEN | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta')"
echo "           TB: $(echo $TB_WRITTEN | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta')"
echo "------------------------------"
echo " Mean write rate:"
echo "        MB/hr: $(echo "scale=3; $MB_WRITTEN / $ON_TIME" | bc | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta')"
echo "------------------------------"
echo " Drive health: ${WEAR_COUNT} %"
echo "------------------------------"

Here's the a sample of the output:

------------------------------
 SSD Status:   /dev/sda
------------------------------
 On time:      2 hr
------------------------------
 Data written:
           MB: 25,098.917
           GB: 24.510
           TB: .023
------------------------------
 Mean write rate:
        MB/hr: 12,549.458
------------------------------
 Drive health: 100 %
------------------------------

This data is accurate, as I only just installed my new 850 Pro.

Method 2:

Alternatively, here's a one-liner to get the TBW only:

echo "GB Written: $(echo "scale=3; $(sudo /usr/sbin/smartctl -A /dev/sda | grep "Total_LBAs_Written" | awk '{print $10}') * 512 / 1073741824" | bc | sed ':a;s/\B[0-9]\{3\}\>/,&/;ta')"

Crucial SSD Lifetime remaining

For Crucial SSD (made by Micron) the question of remaining lifetime is made a little easier.

https://www.micron.com/~/media/documents/products/technical-note/solid-state-storage/tnfd22_client_ssd_smart_attributes.pdf

This doc identifies 202 as Percent Lifetime Remaining. As an example on Ubuntu 16.04 (sudo smartctl /dev/sda1 -a) reports 202 as unknown, but the value of 90 (in my case) matches the description in the pdf, and indicates 90% life remaining. This can be appropriately scaled by the TBW that is given in the crucial.com literature on the drive that you have. Actually, lifetime remaining is rather more useful.


The accepted answer has bloated output, too much useless script-wizardry and hides initial parameter names from smartctl. Here is a better version;

#!/bin/bash

device=${1:-/dev/sda}
sudo smartctl -A $device |awk '
$0 ~ /Power_On_Hours/ { poh=$10; printf "%s / %d hours / %d days / %.2f years\n",  $2, $10, $10 / 24, $10 / 24 / 365.25 }
$0 ~ /Total_LBAs_Written/ {
    lbas=$10;
    bytes=$10 * 512;
    mb= bytes / 1024^2;
    gb= bytes / 1024^3;
    tb= bytes / 1024^4;
    printf "%s / %s  / %d mb / %.1f gb / %.3f tb\n", $2, $10, mb, gb, tb
    printf "mean writes per hour:  / %.2f",  mb/poh
}
$0 ~ /Airflow_Temperature_Cel/ { print $2 " / " $10}
$0 ~ /Wear_Leveling_Count/ { printf "%s / %d (%% health)\n", $2, int($4) }
' |
    sed -e 's:/:@:' |
    sed -e "s\$^\$$device @ \$" |
    column -ts@

sample output:

$ for i in /dev/sd{a,b,c,d}; do ssd-tbw $i;done   |sort -k2,2
/dev/sda    Airflow_Temperature_Cel    49
/dev/sdb    Airflow_Temperature_Cel    49
/dev/sdc    Airflow_Temperature_Cel    45
/dev/sdd    Airflow_Temperature_Cel    47
/dev/sda    mean writes per hour:      655.80
/dev/sdb    mean writes per hour:      646.97
/dev/sdc    mean writes per hour:      874.49
/dev/sdd    mean writes per hour:      733.95
/dev/sda    Power_On_Hours             27292 hours / 1137 days / 3.11 years
/dev/sdb    Power_On_Hours             27300 hours / 1137 days / 3.11 years
/dev/sdc    Power_On_Hours             14432 hours / 601 days / 1.65 years
/dev/sdd    Power_On_Hours             23255 hours / 968 days / 2.65 years
/dev/sda    Total_LBAs_Written         36655329806  / 17898110 mb / 17478.6 gb / 17.069 tb
/dev/sdb    Total_LBAs_Written         36172538301  / 17662372 mb / 17248.4 gb / 16.844 tb
/dev/sdc    Total_LBAs_Written         25846999325  / 12620605 mb / 12324.8 gb / 12.036 tb
/dev/sdd    Total_LBAs_Written         34955224738  / 17067980 mb / 16668.0 gb / 16.277 tb
/dev/sda    Wear_Leveling_Count        93 (% health)
/dev/sdb    Wear_Leveling_Count        93 (% health)
/dev/sdc    Wear_Leveling_Count        95 (% health)
/dev/sdd    Wear_Leveling_Count        94 (% health)

and the one-liner

$ sudo /usr/sbin/smartctl -A /dev/sda | 
     awk '$0~/LBAs/{ printf "TBW %.1f\n", $10 * 512 / 1024^4 }'
TBW 17.1

Tags:

Monitoring

Disk

Ssd

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