Today I sent the following question to Alsoft’s (DiskWarrior) support:
„I noticed entries like this one in my system.log:
May 31 10:11:53 tyrion
/Applications/DiskWarrior.app/Contents/MacOS/DiskWarriorDaemon[932]: [Thu May 31
10:11:53 CEST 2012] : The spare blocks for ATA device 'ST31000528ASQ', serial
number '6VP319CR', appear to be exhausted. (Total Available: 36) (Use Attempts:
229)
I have researched the issue and was surprised that the DiskWarrior manual
doesn’t mention this at all. There is some anecdotal evidence on the web that a
message like that is an indicator for impending drive failure.
So I installed smartmontools, because I wanted to know more details about the
drive’s state. Here’s the relevant output I got:
sudo smartctl -A disk0
smartctl 5.42 2011-10-20 r3458 [i386-apple-darwin10.8.0] (local build)
Copyright (C) 2002-11 by Bruce Allen, http://smartmontools.sourceforge.net
=== START OF READ SMART DATA SECTION ===
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 106 099 006 Old_age Always - 11960322
3 Spin_Up_Time 0x0003 100 100 000 Pre-fail Always - 0
4 Start_Stop_Count 0x0032 100 100 020 Old_age Always - 33
5 Reallocated_Sector_Ct 0x0033 082 082 036 Pre-fail Always - 741
7 Seek_Error_Rate 0x000f 084 060 030 Pre-fail Always - 246300939
9 Power_On_Hours 0x0032 078 078 000 Old_age Always - 19671
10 Spin_Retry_Count 0x0013 100 100 097 Pre-fail Always - 0
12 Power_Cycle_Count 0x0032 100 100 020 Old_age Always - 44
184 End-to-End_Error 0x0032 100 100 099 Old_age Always - 0
187 Reported_Uncorrect 0x0032 100 100 000 Old_age Always - 0
188 Command_Timeout 0x0032 100 100 000 Old_age Always - 0
189 High_Fly_Writes 0x003a 100 100 000 Old_age Always - 0
190 Airflow_Temperature_Cel 0x0022 046 042 045 Old_age Always In_the_past 54 (1 165 58 35 0)
194 Temperature_Celsius 0x0022 054 058 000 Old_age Always - 54 (0 9 0 0 0)
195 Hardware_ECC_Recovered 0x001a 034 021 000 Old_age Always - 11960322
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
From my understanding of the manpage, the actual count of reallocated blocks (as
given by attribute 5) is 741, and the „value“ of 82 is still well above the
critical threshold of 36. What’s more, the attribute 197 shows there are zero
„current pending sectors“, which I understand to mean that all reallocation
requests could be satisfied so far. This seems to run counter to the output of
DiskWarriorDaemon. Could you please explain the discrepancy? Should I replace
the drive after all?“
Their reply was short: „You should replace this hard drive.“
That’s fine (I should be able to replace the drive under AppleCare), but a little low on details. Can anyone explain to me why the output of smartctl seems to be so different? Where do DiskWarrior’s numbers come from?
The „229 use attempts“ appears to be the low 8 bits of the raw value.
741 mod 256 = 229.
As you commented, the reallocated sector count is well within acceptable limits, especially for a 20000 hour old disk, and in this case I would only be concerned if the reallocated sector count were rapidly increasing.
However, I would also look at cooling – your HDD has reached 58C in the past.
Thanks for your reply. Your idea regarding the value of 229 makes sense. The message from DiskWarriorDaemon seems to have been caused by a software malfunction anyway, because it never came back after a reboot. I’ve noticed the temperature as well – the maximum is up to 59C now, but there isn’t much I can do about that: it’s an iMac.
Das hat mir auch weitergeholfen, vielen Dank!
Grüße
Martin
Die von DiskWarrior finde ich übrigens ziemlich inkompetent…
Nochmals danke!