Monitoring wear leveling [LWN.net]

Monitoring wear leveling

Posted Feb 19, 2011 2:20 UTC (Sat) by ayers (subscriber, #53541)
Parent article: Optimizing Linux with cheap flash drives

I keep wondering whether there is a standard interface (SMART attribute?) which measures/monitors the wear leveling to indicate when it's time to replace the SSD/SD cards before the risk of data loss exceeds some probability.

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Monitoring wear leveling

Posted Feb 20, 2011 0:47 UTC (Sun) by rwa (subscriber, #69887) [Link]

Well not really standard but Intel SSDs support something like this. This is from one of our build servers:

ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  3 Spin_Up_Time            0x0020   100   100   000    Old_age   Offline      -       0
  4 Start_Stop_Count        0x0030   100   100   000    Old_age   Offline      -       0
  5 Reallocated_Sector_Ct   0x0032   100   100   000    Old_age   Always       -       11
  9 Power_On_Hours          0x0032   100   100   000    Old_age   Always       -       3516
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       26
192 Unsafe_Shutdown_Count   0x0032   100   100   000    Old_age   Always       -       11
225 Host_Writes_32MiB       0x0030   200   200   000    Old_age   Offline      -       715312
226 Workld_Media_Wear_Indic 0x0032   100   100   000    Old_age   Always       -       3701
227 Workld_Host_Reads_Perc  0x0032   100   100   000    Old_age   Always       -       1
228 Workload_Minutes        0x0032   100   100   000    Old_age   Always       -       16928063
232 Available_Reservd_Space 0x0033   099   099   010    Pre-fail  Always       -       0
233 Media_Wearout_Indicator 0x0032   096   096   000    Old_age   Always       -       0
184 End-to-End_Error        0x0033   100   100   099    Pre-fail  Always       -       0

The wearout indicator (233) started ad 100 and is no at 96 after writing 21TB in almost 5 Months. It's an 160GB X-25M from Intel.

Monitoring wear leveling

Posted Feb 20, 2011 3:33 UTC (Sun) by dougg (subscriber, #1894) [Link]

# smartctl -a /dev/sda
...
Model Family: Intel X18-M/X25-M/X25-V G2 SSDs
...
9 Power_On_Hours 0x0032 100 100 000 Old_age Always - 1028
...
233 Media_Wearout_Indicator 0x0032 099 099 000 Old_age Always - 0
...

No need to wonder.