SMART monitoring on Mac OS X

Unfortunately, I've recently had reason to want to check the SMART status of my PowerBook's internal disk.

Apple's Disk Utility will tell you a simple pass/fail summary of the SMART status of the disk, but it won't go into any detail, show you logs, or details of particular errors. What's more, I believe that it only looks at certain classes of errors to determing the Verified of Failing status, and so if the drive is experiencing errors, such as it's firmware silently remapping sectors, it's still shown as A-OK.

I decided to go hunting for some more useful utilities, and firstly discovered SMARTReporter which displays an icon in the menu bar showing you a visual status of the disk. This utility, however, appears to use the same criteria as Disk Utility for determining as simple pass/fail status, so in this particular case isn't that useful to me. It is handy in a more general sense as it can monitor multiple disks, and upon a SMART failure it can do any combination of: pop up an alert dialog, execute another program or send emails to multiple addresses.

So, digging a bit deeper, I then found the smartmontools which consists of smartctl and smartd that together will report on a whole lot of low-level SMART information, including showing the drive's error log, and other useful information.

It shows me that although Disk Utility et al think that my disk is OK, it's actually logged 2732 errors over it's lifetime and also reports on thresholds the drive is recording, as shown below:

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 096 096 050 Pre-fail Always - 0
2 Throughput_Performance 0x0005 100 100 050 Pre-fail Offline - 0
3 Spin_Up_Time 0x0027 100 100 001 Pre-fail Always - 1356
4 Start_Stop_Count 0x0032 100 100 000 Old_age Always - 2361
5 Reallocated_Sector_Ct 0x0033 100 100 050 Pre-fail Always - 695
7 Seek_Error_Rate 0x000b 100 100 050 Pre-fail Always - 0
8 Seek_Time_Performance 0x0005 100 100 050 Pre-fail Offline - 0
9 Power_On_Hours 0x0032 089 089 000 Old_age Always - 4727
10 Spin_Retry_Count 0x0033 147 100 030 Pre-fail Always - 0
12 Power_Cycle_Count 0x0032 100 100 000 Old_age Always - 2268
192 Power-Off_Retract_Count 0x0032 100 100 000 Old_age Always - 9
193 Load_Cycle_Count 0x0032 055 055 000 Old_age Always - 456326
194 Temperature_Celsius 0x0022 100 100 000 Old_age Always - 44 (Lifetime Min/Max 11/55)
196 Reallocated_Event_Count 0x0032 100 100 000 Old_age Always - 291
197 Current_Pending_Sector 0x0032 100 100 000 Old_age Always - 14
198 Offline_Uncorrectable 0x0030 100 100 000 Old_age Offline - 0
199 UDMA_CRC_Error_Count 0x0032 200 200 000 Old_age Always - 0
220 Disk_Shift 0x0002 100 100 000 Old_age Always - 8343
222 Loaded_Hours 0x0032 094 094 000 Old_age Always - 2636
223 Load_Retry_Count 0x0032 100 100 000 Old_age Always - 0
224 Load_Friction 0x0022 100 100 000 Old_age Always - 0
226 Load-in_Time 0x0026 100 100 000 Old_age Always - 222
240 Head_Flying_Hours 0x0001 100 100 001 Pre-fail Offline - 0

It also shows the most recent five errors, one of which looks like:

Error 32 occurred at disk power-on lifetime: 4727 hours (196 days + 23 hours)
When the command that caused the error occurred, the device was active or idle.

After command completion occurred, registers were:
ER ST SC SN CL CH DH
-- -- -- -- -- -- --
10 51 f0 b8 bd 81 46 Error: IDNF 240 sectors at LBA = 0x0681bdb8 = 109166008

Commands leading to the command that caused the error were:
CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name
-- -- -- -- -- -- -- -- ---------------- --------------------
25 00 f8 b0 bb 81 40 00 09:40:17.577 READ DMA EXT
35 00 50 e3 27 04 40 00 09:40:17.577 WRITE DMA EXT
35 00 08 b8 c5 8f 40 00 09:40:16.283 WRITE DMA EXT
35 00 08 98 0d 90 40 00 09:40:16.283 WRITE DMA EXT
25 00 08 80 16 8a 40 00 09:40:14.891 READ DMA EXT


So, even though my hard drive is actually logging read/write errors, Disk Utility thinks it's all peachy. The drive has been playing up a little bit this arvo - running OS X just all of a sudden got very s-l-o-w. CPU usage was minimal, there weren't hundreds of threads in the run queue, VM usage was acceptable, even disk I/Os were reporting low numbers, but anything that was disk-related (so just about everything) was crawling along. Switching tasks was quick, scrolling through windows was fine, but even at the terminal, whenever you entered a command, there was a big pause before it ran, and then afterwards again as it had to reload the shell, another huge pause.

I'm now trying to copy my home folder off the drive (as a 5GB FileVault sparse image) and then I will attempt recovery of other files, but it seems that the drive is on it's way out.

Once I've got my FileVault image off, I'm going to shut the PowerBook down for the night, and give it a break, and then try and make a diskimage of the whole drive tomorrow morning. Wish me luck!