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"SMART Usage Attribute: 194 Temperature_Celsius changed from 146 to 150". This is on CentOS 6.6.

What does this really mean? Is the drive really hot or is this perhaps a software bug? The drive is an eSATA 2TB drive and it feels cool to the touch and the server located in a basement is 70F.

# smartctl -A /dev/sdb
smartctl 5.43 2012-06-30 r3573 [x86_64-linux-2.6.32-504.16.2.el6.x86_64] (local build)
Copyright (C) 2002-12 by Bruce Allen, http://smartmontools.sourceforge.net

=== START OF READ SMART DATA SECTION ===
SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000b   100   100   016    Pre-fail  Always       -       0
  2 Throughput_Performance  0x0005   134   134   054    Pre-fail  Offline      -       89
  3 Spin_Up_Time            0x0007   123   123   024    Pre-fail  Always       -       507 (Average 505)
  4 Start_Stop_Count        0x0012   100   100   000    Old_age   Always       -       89
  5 Reallocated_Sector_Ct   0x0033   100   100   005    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000b   100   100   067    Pre-fail  Always       -       0
  8 Seek_Time_Performance   0x0005   135   135   020    Pre-fail  Offline      -       26
  9 Power_On_Hours          0x0012   096   096   000    Old_age   Always       -       29541
 10 Spin_Retry_Count        0x0013   100   100   060    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       71
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age   Always       -       205
193 Load_Cycle_Count        0x0012   100   100   000    Old_age   Always       -       205
**194 Temperature_Celsius     0x0002   150   150   000    Old_age   Always       -       40 (Min/Max 20/49)**
196 Reallocated_Event_Count 0x0032   100   100   000    Old_age   Always       -       0
197 Current_Pending_Sector  0x0022   100   100   000    Old_age   Always       -       0
198 Offline_Uncorrectable   0x0008   100   100   000    Old_age   Offline      -       0
199 UDMA_CRC_Error_Count    0x000a   200   200   000    Old_age   Always       -       9
13

That is just SMART attribute value. It is not the temperature in any regular unit. (it is more like a number between 255 (really really cold) and 0 (really really hot), depending on drive what is hot and what not)

If you want to see the temp of your drive use smartctl -A /dev/sdx

You'll get table like this:

ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
194 Temperature_Celsius     0x0022   107   097   000    Old_age   Always       -       45

RAW_VALUE is what you're looking for ... (my drive is quite warm at 45°C)

VALUE is the attribute value and when it gets below THRESH, the drive is getting ready to ask for replacement. (Not all attributes have threshold, just like my temperature)

With regards to what is hot and what is not, it really depends on drive. There is a somewhat dated paper from Google on drive failure rates, which states that drives around 40°C have the lowest failure rates (at least for google and in 2007). I remember reading another paper (can't find it now) which stated, that high temperature is not a problem for hard drive. Sharp and frequent temperature changes can cause the disk to fail sooner. So as long as the drive temp is pretty stable (you can monitor that using something like munin), you should be fine.

smartd is reporting any changes in attributes. It does not mean that there is something wrong.

  • 1
    Thanks. Please see above, I updated this with the smartctl output. RAW_VALUE is 40. That is 40 degrees Celsius, which is 104F. Is that considered hot? Or getting hot and it's logging it because it might be a dangerous trend? But the Min/Max is 20/49, so it doesn't sound like it's too hot at least yet, – Edward_178118 May 19 '15 at 23:20
  • 1
    @Edward_178118 updated the answer, hope it helps. – Fox May 19 '15 at 23:33
  • So the threshold values of 150, had nothing to do with being 150C? – Edward_178118 May 20 '15 at 14:38
  • Exactly. 150 would be way too hot. Even too hot for a CPU, which gets heatsink, to stay below 80 or so. – Fox May 20 '15 at 14:43

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