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Wear level and total bytes written in SATA SSD

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On a Samsung SATA SSD, i.e. non NVMe disk, the following are the SmartCtl values that are obtained by running the command sudo smartctl -a /dev/sda, SMART Attributes Data Structure revision number: 1 Vendor Specific SMART Attributes with Thresholds: ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE 5 Reallocated_Sector_Ct 0x0033 100 100 010 Pre-fail Always - 0 177 Wear_Leveling_Count 0x0013 099 099 000 Pre-fail Always - 18 241 Total_LBAs_Written 0x0032 099 099 000 Old_age Always - 10452411061 On the same disk when the command sudo skdump /dev/sda is run the following is the output. Overall Status: GOOD ID# Name Value Worst Thres Pretty Raw Type Updates Good Good/Past 5 reallocated-sector-count 100 100 10 0 sectors 0x000000000000 prefail online yes yes 177 wear-leveling-count 99 99 0 18 0x120000000000 prefail online n/a n/a 241 total-lbas-written 99 99 0 350725.752 TB 0x3d9b036f0200 old-age online n/a n/a For this I had the following queries 1) skdump command is returning a value of 350725.752 TB written, i.e. total-lbas-written. Is this correct? 2) Based on the answer provided in another post the output of smartctl for total-lbas-written is 10452411061, which equates to 4.86 TB written (i.e. 10452411061/2/1024/1024/1024). This differs significantly from the value reported by the skdump command. Is this value accurate? The Sector size is 512 bytes. 3) After looking at various posts in SuperUser and StackExchange, for samsung ssd drives the value of Wear_Leveling_Count determines how much wear leveling has occurred on the SSD. But it is not clear what figure should be considered? The figure of the column **RAW_VALUE** or **VALUE** column. And does having RAW_VALUE of 18 implies that only 18% of the SSD life is left?
Asked by KDM (116 rep)
May 27, 2025, 08:12 AM
Last activity: May 27, 2025, 10:17 AM