OT probably, help please

[James Linder]

> On 23 Jan 2015, at 12:42 am, William H. Magill <magill at mac.com> wrote:
> 
>>> I cannot explain why a (normally) rational, sane thinking idiot did not make that his first port of call (beautifully synced)
>>> 
>>> Jan 21 00:04:34 haycorn kernel[0]: disk0s2: I/O error.
>>> 
>>> Thanks everybody, and sorry for being an idiot
>> 
>> I wouldn't immediately think about disk i/o errors either from the symptoms you described (not for short freezes in anyway). Not with an hdd anyway.
>> What's in your logs around those I/O error messages, and what do the smartmontools (in MacPorts) tell about the disk's health? smartctl -a /dev/disk0 and do run smartctl -t long /dev/disk0 (disabling disk spin down for the duration of the test as that would interrupt it)?
>> 
>> A bit too many reports of comparable symptoms in 10.9 somehow related to disk I/O errors for my comfort zone. OS X wouldn't be doing something low level that somehow stresses the disk hardware I hope?

I confess to bias suspecting yosemite before anything else!
smartctl -a gives zillions of errors eg

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000e   078   077   006    Old_age   Always       -       183829319
  3 Spin_Up_Time            0x0003   100   100   000    Pre-fail  Always       -       0
  4 Start_Stop_Count        0x0032   099   099   020    Old_age   Always       -       1749
  5 Reallocated_Sector_Ct   0x0033   100   100   036    Pre-fail  Always       -       0
  7 Seek_Error_Rate         0x000f   081   060   030    Pre-fail  Always       -       147598082
  9 Power_On_Hours          0x0032   078   078   000    Old_age   Always       -       19827
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail  Always       -       0
 12 Power_Cycle_Count       0x0032   099   099   020    Old_age   Always       -       1505
184 End-to-End_Error        0x0032   100   100   099    Old_age   Always       -       0
187 Reported_Uncorrect      0x0032   001   001   000    Old_age   Always       -       34330
188 Command_Timeout         0x0032   100   100   000    Old_age   Always       -       0
189 High_Fly_Writes         0x003a   099   099   000    Old_age   Always       -       1
190 Airflow_Temperature_Cel 0x0022   058   040   045    Old_age   Always   In_the_past 42 (3 248 42 24 0)
194 Temperature_Celsius     0x0022   042   060   000    Old_age   Always       -       42 (0 16 0 0 0)
195 Hardware_ECC_Recovered  0x001a   038   025   000    Old_age   Always       -       183829319
197 Current_Pending_Sector  0x0012   100   100   000    Old_age   Always       -       2
198 Offline_Uncorrectable   0x0010   100   100   000    Old_age   Offline      -       2
199 UDMA_CRC_Error_Count    0x003e   200   200   000    Old_age   Always       -       0

James