How can I monitor the TBW on my Samsung SSD?

Question

As is common knowledge, SSDs have a limited number of PE (Program-Erase) cycles before the NAND cells die.

Therefore, it is very helpful to know how much data has been written to your SSD, in order to determine how much longer it will last before the NAND dies.

I have a Samsung 850 Pro 512GB SSD, and I am running Ubuntu 14.04.

How can I get the TBW (Total-Bytes-Written) for my drive?

score 41 · Accepted Answer · edited Jul 21 '23 at 16:05

FULL DISCLOSURE: The script/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.

Important note

This will only report accurate numbers for Samsung SSDs.
You need to have smartctl installed, from the package smartmontools.

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

Here's 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')"

Daniel C · Answer 2 · 2021-06-03T20:13:09.677

How to find the information

We can use smartctl to find the value of TBW.

Install smartctl with $ sudo apt install smartmontools
Get sector size and LBA written with $ sudo smartctl -Ai /dev/sda in this case for device /dev/sda
Some math: [sector size] * [LBA written] / 1024^3 = X GiB written so far

Example for device /dev/sda

$ sudo smartctl -Ai /dev/sda | grep -E 'Sector Size|Total_LBAs_Written'
Sector Size:      512 bytes logical/physical
241 Total_LBAs_Written      0x0032   099   099   000    Old_age   Always       -       1214641768
$ calc 1214641768*512/1024^3
    579.186328887939453125

In this case the sector size is 512 bytes, which is common, and total LBA written is 1214641768. The result is 579 GiB written so far. This makes sense since this drive is relatively new.

_{Command calc can be install with $ sudo apt install calc or use something else.}

More info

The command $ sudo smartctl -A /dev/sda gives information on "vendor specific SMART Attributes" meaning what your drive shows may not be the same as this one. In the example I used a Samsung SSD which has the needed information.

Kingston SSD

Following what @JuliSmz said in their comment, and this PDF, I suspect Total_LBAs_Written returned by (at least some) Kingston SSDs is already in GB.

Look for id 241 on the last page of the PDF. It says:

Description: Indicates the number of bytes (in 1 GB resolution) written to the drive by a host system, over the life of the drive.

Rationale: This Attribute returns a byte count, in units of gigabytes at an update resolution of 1 GBytes. The count represents the number of bytes written. The Attribute reads 0 until the number of bytes written reaches 1GB; at additional GB the Attribute increments to a value of 1 (decimal).

Note: Client firmware older than 520ABBF0 and Enterprise firmware older than 510ABBF0 did not update resolution until 64GB of data was written to the drive.

score 6 · Answer 3 · edited Jul 22 '23 at 02:59

6

Crucial SSD

For Crucial SSD percentage lifetime remaining see here.

This doc identifies 202 as Percent Lifetime Remaining. As an example, on Ubuntu 16.04 (sudo smartctl /dev/sda1 -a, part of smartmontools) reports 202 as unknown, but the value of 90 indicates 90% life remaining. On Ubuntu 20.04, the Lifetime Remaining is recognized and listed correctly.

edited Jul 22 '23 at 02:59

Pablo Bianchi

17,371

answered Nov 05 '18 at 13:59

Steve C

61

Ярослав Рахматуллин · Answer 4 · 2023-07-26T04:18:32.373

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

Fritzi · Answer 5 · 2024-04-06T23:25:02.727

Thanks for the inspiration, slightly modified the scripts, works for my SSDs. I had to multiply the sector size 512 by a correction factor 65535, please check, if you need it. If not sure, compare with Windows Progs like CrystalDiskInfo, SSD-Z.

#!/bin/bash
Usage e.g. : bash ssd-tbw.bash
or:          bash ssd-tbw.bash /dev/sdb
or:          for i in /dev/sd{a,b,c,d}; do bash ssd-tbw.bash $i;done
Source : https://askubuntu.com/questions/865792/how-can-i-monitor-the-tbw-on-my-samsung-ssd
device=${1:-/dev/sda}
#device=${1:-/dev/sdb}
echo DEVICE : $device
#DEVICE
sudo /usr/sbin/smartctl -a $device | grep -i 'device'
sector size 512, correction factor 64k = 65535, see line : bytes = ...
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 * 65535;
    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/ { printf "%s / %d (%% health)\n", $2, int($4) }
' |
    sed -e 's:/:@:' |
    sed -e "s$^$$device @ $" |
    column -ts@
#Health only :
sudo /usr/sbin/smartctl -H $device
wait for keyboard input, helpful if executed by launcher file
read -p "Press Enter to continue" </dev/tty

And a little launcher file for the desktop 'ssd-tbw.desktop', please edit USER etc. for your needs :

[Desktop Entry]
Version=1.0
Exec=/home/USER/ssd-tbw.bash
Name=Smartctl Script
GenericName=Smartctl Script
Comment=Smartctl Script
Encoding=UTF-8
Terminal=true
Type=Application
Categories=Application;
Name[de_DE]=Smartctl Check

How can I monitor the TBW on my Samsung SSD?

5 Answers5

FULL DISCLOSURE: The script/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.

Important note

Method 1

Variables

Get total data written...

Get SMART attributes

Extract required attributes

Convert LBAs -> bytes

Output results...

Method 2

How to find the information

Example for device /dev/sda

More info

Kingston SSD

Crucial SSD

Usage e.g. : bash ssd-tbw.bash

or: bash ssd-tbw.bash /dev/sdb

or: for i in /dev/sd{a,b,c,d}; do bash ssd-tbw.bash $i;done

Source : https://askubuntu.com/questions/865792/how-can-i-monitor-the-tbw-on-my-samsung-ssd

sector size 512, correction factor 64k = 65535, see line : bytes = ...

wait for keyboard input, helpful if executed by launcher file

Linked