I recently got a Samsung SSD. I have debian wheezy installed on it. I carry it around in a USB enclosure and boot both my work and home computers from it. How can I ensure that the system properly powers down the drive during shutdown? The following SMART metrics seem to indicate that it doesn't:

 12 Power_Cycle_Count  0x0032  099   099   000    Old_age  Always      -       24
235 Unknown_Attribute  0x0012  099   099   000    Old_age  Always      -       23

I believe the numbers indicate the drive has been powered up 24 times and has lost power unexpectedly 23 times, i.e. every power down. The metrics are described on Samsung's website as follows:

ID # 12 Power-On Count

The raw value of this attribute reports the cumulative number of power on/off cycles. This includes both sudden power off and normal power off cases.

ID # 235 Power Recovery Count

A count of the number of sudden power off cases. If there is a sudden power off, the firmware must recover all of the mapping and user data during the next power on. This is a count of the number of times this has happened.

I read that unexpected power loss is bad for an SSD.

Edit: Now I'm not sure this is a real question. I tried attaching the drive to a different system, putting it to sleep with hdparm -Y /dev/sdX, and then disconnecting the USB cable. It still increments the power recovery count. I tried this with three different enclosures. I think I'll take this issue to Samsung.

  • Hmmm, maybe a driver issue. I have a crucial m4 with a count of 2000 for ID 12, no listing for 235 but (different manufacturer of course) 0 for 174, "Unexpect_Power_Loss_Ct".
    – goldilocks
    Dec 14 '14 at 14:51

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