For a few weeks now, smartd has been reporting that it is skipping some of its scheduled self-tests on the weekends:
Apr 24 18:29:32 calvin smartd[4758]: Device: /dev/sda, skip scheduled Offline Immediate Test; 40% remaining of current Self-Test. Apr 24 18:29:33 calvin smartd[4758]: Device: /dev/sdb, skip scheduled Offline Immediate Test; 50% remaining of current Self-Test.
The drives in this RAID-1 array are set to run an offline test four times a day, a short self-test at 2am every day, and a long self-test on Saturdays at 2am. For some reason, it looks like the long self-test is taking longer, causing the other scheduled tests to be skipped.
First question: is this a sign of likely drive failure?
Then today, smartd reported that a self-test failed. Here is the output of smartctl -a /dev/sdb:
smartctl version 5.38 [i686-pc-linux-gnu] Copyright (C) 2002-8 Bruce Allen
Home page is http://smartmontools.sourceforge.net/
=== START OF INFORMATION SECTION ===
Model Family: Seagate Barracuda 7200.8 family
Device Model: ST3250823AS
Serial Number: 3ND1GNBC
Firmware Version: 3.03
User Capacity: 250,059,350,016 bytes
Device is: In smartctl database [for details use: -P show]
ATA Version is: 7
ATA Standard is: Exact ATA specification draft version not indicated
Local Time is: Sun Apr 25 13:15:34 2010 EDT
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED
General SMART Values:
Offline data collection status: (0x82) Offline data collection activity
was completed without error.
Auto Offline Data Collection: Enabled.
Self-test execution status: ( 0) The previous self-test routine completed
without error or no self-test has ever
been run.
Total time to complete Offline
data collection: ( 430) seconds.
Offline data collection
capabilities: (0x5b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
No Conveyance Self-test supported.
Selective Self-test supported.
SMART capabilities: (0x0003) Saves SMART data before entering
power-saving mode.
Supports SMART auto save timer.
Error logging capability: (0x01) Error logging supported.
General Purpose Logging supported.
Short self-test routine
recommended polling time: ( 1) minutes.
Extended self-test routine
recommended polling time: ( 84) minutes.
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 0x000f 047 039 006 Pre-fail Always - 168450357
3 Spin_Up_Time 0x0003 098 098 000 Pre-fail Always - 0
4 Start_Stop_Count 0x0032 100 100 020 Old_age Always - 33
5 Reallocated_Sector_Ct 0x0033 100 100 036 Pre-fail Always - 9
7 Seek_Error_Rate 0x000f 087 060 030 Pre-fail Always - 654745480
9 Power_On_Hours 0x0032 055 055 000 Old_age Always - 40141
10 Spin_Retry_Count 0x0013 100 100 097 Pre-fail Always - 0
12 Power_Cycle_Count 0x0032 100 100 020 Old_age Always - 51
194 Temperature_Celsius 0x0022 037 062 000 Old_age Always - 37 (0 17 0 0)
195 Hardware_ECC_Recovered 0x001a 047 039 000 Old_age Always - 168450357
197 Current_Pending_Sector 0x0012 100 100 000 Old_age Always - 0
198 Offline_Uncorrectable 0x0010 100 100 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x003e 200 200 000 Old_age Always - 0
200 Multi_Zone_Error_Rate 0x0000 100 253 000 Old_age Offline - 0
202 TA_Increase_Count 0x0032 100 253 000 Old_age Always - 0
SMART Error Log Version: 1
No Errors Logged
SMART Self-test log structure revision number 1
Num Test_Description Status Remaining LifeTime(hours) LBA_of_first_error
# 1 Short offline Completed without error 00% 40131 -
# 2 Extended offline Completed: read failure 30% 40129 379795511
# 3 Short offline Completed without error 00% 40084 -
# 4 Short offline Completed without error 00% 40060 -
# 5 Short offline Completed without error 00% 40036 -
# 6 Short offline Completed without error 00% 40013 -
# 7 Short offline Completed without error 00% 39990 -
# 8 Extended offline Completed without error 00% 39977 -
# 9 Short offline Completed without error 00% 39919 -
#10 Short offline Completed without error 00% 39895 -
#11 Short offline Completed without error 00% 39872 -
#12 Short offline Completed without error 00% 39848 -
#13 Short offline Completed without error 00% 39824 -
#14 Short offline Completed without error 00% 39801 -
#15 Extended offline Completed without error 00% 39789 -
#16 Short offline Completed without error 00% 39754 -
#17 Short offline Completed without error 00% 39732 -
#18 Short offline Completed without error 00% 39707 -
#19 Short offline Completed without error 00% 39683 -
#20 Short offline Completed without error 00% 39660 -
#21 Short offline Completed without error 00% 39636 -
SMART Selective self-test log data structure revision number 1
SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
1 0 0 Not_testing
2 0 0 Not_testing
3 0 0 Not_testing
4 0 0 Not_testing
5 0 0 Not_testing
Selective self-test flags (0x0):
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.
Given that this drive is about 4.5 years old, I am probably tempting fate by keeping it in service.
SMART doesn't seem to get much respect as a reliable way to predict drive failure. What else can I use to get an early indication of drive failure?
Some SMART parameters, such as reallocation counts tend to be good indications of future disk failures, while other parameters are less useful. Still SMART is the best way to get low level reliability information about your disk unless you have the debugging tools that the HD producers use.
If you are interested in hard-disk failures on a more aggregated level I suggest you have a look at the survey a team at Google did, where they also discuss the performance of SMART monitoring and other important factors in HD reliability.