Hard Disk Monitoring

I have been getting strange log entries and sudden increases of some SMART attributes in HDS, but Smartmontools shows no errors logged. I realize HDS only reports what's recorded in the SMART, but why the sudden increases as if HDS was unable to read the SMART at times and then when it could there was a dramatic increase in the attributes value. One day HDS reported that Hard Drive failure was imminent and health dropped from 100% to 9%, but before I could get another drive to transfer the data, HDS showed that the health had been restored to 100% and all 7000 pending sectors disappeared without being reallocated.

HDS logged that the Power Off Retract Cycle Count decreased between 2/20 and 2/26. How is this possible with an incremental attribute?

Also, why can't HDS incorporate viewing the error log stored on the hard drive like Smartmontools?

G:\>smartctl -x -d sat /dev/sdc
smartctl 6.5 2016-05-07 r4318 [x86_64-w64-mingw32-win10] (sf-6.5-1)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family: Seagate Archive HDD
Device Model: ST8000AS0002-1NA17Z
Serial Number: Z840SLRZ
LU WWN Device Id: 5 000c50 092e863a8
Firmware Version: RT17
User Capacity: 8,001,563,222,016 bytes [8.00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 5980 rpm
Device is: In smartctl database [for details use: -P show]
ATA Version is: ACS-2, ACS-3 T13/2161-D revision 3b
SATA Version is: SATA 3.1, 6.0 Gb/s (current: 3.0 Gb/s)
Local Time is: Thu Mar 09 10:47:40 2017 EST
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
AAM feature is: Unavailable
APM feature is: Unavailable
Rd look-ahead is: Enabled
Write cache is: Enabled
ATA Security is: Disabled, NOT FROZEN [SEC1]
Wt Cache Reorder: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED
See vendor-specific Attribute list for marginal Attributes.

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: ( 0) seconds.
Offline data collection
capabilities: (0x7b) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
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: ( 948) minutes.
Conveyance self-test routine
recommended polling time: ( 2) minutes.
SCT capabilities: (0x30b5) SCT Status supported.
SCT Feature Control supported.
SCT Data Table supported.

SMART Attributes Data Structure revision number: 10
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE
1 Raw_Read_Error_Rate POSR-- 118 099 006 - 172161240
3 Spin_Up_Time PO---- 092 091 000 - 0
4 Start_Stop_Count -O--CK 100 100 020 - 215
5 Reallocated_Sector_Ct PO--CK 100 100 010 - 0
7 Seek_Error_Rate POSR-- 071 060 030 - 12927858388
9 Power_On_Hours -O--CK 099 099 000 - 1231
10 Spin_Retry_Count PO--C- 100 100 097 - 0
12 Power_Cycle_Count -O--CK 100 100 020 - 165
183 Runtime_Bad_Block -O--CK 100 100 000 - 0
184 End-to-End_Error -O--CK 100 100 099 - 0
187 Reported_Uncorrect -O--CK 100 100 000 - 0
188 Command_Timeout -O--CK 100 097 000 - 12885098511
189 High_Fly_Writes -O-RCK 100 100 000 - 0
190 Airflow_Temperature_Cel -O---K 049 037 045 Past 51 (Min/Max 48/52 #1855)
191 G-Sense_Error_Rate -O--CK 100 100 000 - 0
192 Power-Off_Retract_Count -O--CK 100 100 000 - 1942
193 Load_Cycle_Count -O--CK 099 099 000 - 3251
194 Temperature_Celsius -O---K 051 063 000 - 51 (0 16 0 0 0)
195 Hardware_ECC_Recovered -O-RC- 118 099 000 - 172161240
197 Current_Pending_Sector -O--C- 100 079 000 - 0
198 Offline_Uncorrectable ----C- 100 079 000 - 0
199 UDMA_CRC_Error_Count -OSRCK 200 200 000 - 0
240 Head_Flying_Hours ------ 100 253 000 - 917 (13 53 0)
241 Total_LBAs_Written ------ 100 253 000 - 31210470595
242 Total_LBAs_Read ------ 100 253 000 - 20477874789855
||||||_ K auto-keep
|||||__ C event count
||||___ R error rate
|||____ S speed/performance
||_____ O updated online
|______ P prefailure warning

General Purpose Log Directory Version 1
SMART Log Directory Version 1 [multi-sector log support]
Address Access R/W Size Description
0x00 GPL,SL R/O 1 Log Directory
0x01 SL R/O 1 Summary SMART error log
0x02 SL R/O 5 Comprehensive SMART error log
0x03 GPL R/O 5 Ext. Comprehensive SMART error log
0x04 GPL,SL R/O 8 Device Statistics log
0x06 SL R/O 1 SMART self-test log
0x07 GPL R/O 1 Extended self-test log
0x08 GPL R/O 8 Power Conditions log
0x09 SL R/W 1 Selective self-test log
0x10 GPL R/O 1 SATA NCQ Queued Error log
0x11 GPL R/O 1 SATA Phy Event Counters log
0x21 GPL R/O 8 Write stream error log
0x22 GPL R/O 8 Read stream error log
0x24 GPL R/O 512 Current Device Internal Status Data log
0x30 GPL,SL R/O 9 IDENTIFY DEVICE data log
0x80-0x9f GPL,SL R/W 16 Host vendor specific log
0xa1 GPL,SL VS 24 Device vendor specific log
0xa2 GPL VS 8160 Device vendor specific log
0xa8-0xa9 GPL,SL VS 136 Device vendor specific log
0xab GPL VS 1 Device vendor specific log
0xb0 GPL VS 9048 Device vendor specific log
0xbe-0xbf GPL VS 65528 Device vendor specific log
0xc0 GPL,SL VS 1 Device vendor specific log
0xc1 GPL,SL VS 16 Device vendor specific log
0xd1 GPL VS 80 Device vendor specific log
0xd3 GPL VS 1920 Device vendor specific log
0xda GPL,SL VS 8 Device vendor specific log
0xe0 GPL,SL R/W 1 SCT Command/Status
0xe1 GPL,SL R/W 1 SCT Data Transfer

SMART Extended Comprehensive Error Log Version: 1 (5 sectors)
No Errors Logged

SMART Extended Self-test Log Version: 1 (1 sectors)
No self-tests have been logged. [To run self-tests, use: smartctl -t]

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.

SCT Status Version: 3
SCT Version (vendor specific): 522 (0x020a)
SCT Support Level: 1
Device State: Active (0)
Current Temperature: 52 Celsius
Power Cycle Min/Max Temperature: 48/52 Celsius
Lifetime Min/Max Temperature: 16/63 Celsius
Under/Over Temperature Limit Count: 0/0

SCT Temperature History Version: 2
Temperature Sampling Period: 3 minutes
Temperature Logging Interval: 59 minutes
Min/Max recommended Temperature: 14/55 Celsius
Min/Max Temperature Limit: 10/60 Celsius
Temperature History Size (Index): 128 (63)

Index Estimated Time Temperature Celsius
64 2017-03-04 05:25 50 *******************************
65 2017-03-04 06:24 50 *******************************
66 2017-03-04 07:23 51 ********************************
67 2017-03-04 08:22 55 ************************************
68 2017-03-04 09:21 51 ********************************
69 2017-03-04 10:20 55 ************************************
70 2017-03-04 11:19 55 ************************************
71 2017-03-04 12:18 56 *************************************
72 2017-03-04 13:17 51 ********************************
73 2017-03-04 14:16 51 ********************************
74 2017-03-04 15:15 51 ********************************
75 2017-03-04 16:14 ? -
76 2017-03-04 17:13 52 *********************************
77 2017-03-04 18:12 47 ****************************
78 2017-03-04 19:11 45 **************************
79 2017-03-04 20:10 53 **********************************
80 2017-03-04 21:09 54 ***********************************
... ..( 2 skipped). .. ***********************************
83 2017-03-05 00:06 54 ***********************************
84 2017-03-05 01:05 56 *************************************
85 2017-03-05 02:04 56 *************************************
86 2017-03-05 03:03 55 ************************************
87 2017-03-05 04:02 57 **************************************
88 2017-03-05 05:01 58 ***************************************
89 2017-03-05 06:00 59 ****************************************
90 2017-03-05 06:59 58 ***************************************
91 2017-03-05 07:58 57 **************************************
92 2017-03-05 08:57 56 *************************************
93 2017-03-05 09:56 55 ************************************
94 2017-03-05 10:55 53 **********************************
95 2017-03-05 11:54 56 *************************************
96 2017-03-05 12:53 55 ************************************
97 2017-03-05 13:52 50 *******************************
98 2017-03-05 14:51 49 ******************************
99 2017-03-05 15:50 49 ******************************
100 2017-03-05 16:49 52 *********************************
101 2017-03-05 17:48 53 **********************************
102 2017-03-05 18:47 57 **************************************
103 2017-03-05 19:46 55 ************************************
104 2017-03-05 20:45 58 ***************************************
105 2017-03-05 21:44 54 ***********************************
106 2017-03-05 22:43 53 **********************************
107 2017-03-05 23:42 54 ***********************************
108 2017-03-06 00:41 53 **********************************
109 2017-03-06 01:40 52 *********************************
110 2017-03-06 02:39 53 **********************************
111 2017-03-06 03:38 52 *********************************
112 2017-03-06 04:37 55 ************************************
113 2017-03-06 05:36 57 **************************************
114 2017-03-06 06:35 56 *************************************
115 2017-03-06 07:34 59 ****************************************
116 2017-03-06 08:33 55 ************************************
117 2017-03-06 09:32 54 ***********************************
118 2017-03-06 10:31 55 ************************************
119 2017-03-06 11:30 54 ***********************************
120 2017-03-06 12:29 53 **********************************
121 2017-03-06 13:28 55 ************************************
122 2017-03-06 14:27 53 **********************************
123 2017-03-06 15:26 47 ****************************
124 2017-03-06 16:25 48 *****************************
125 2017-03-06 17:24 49 ******************************
126 2017-03-06 18:23 49 ******************************
127 2017-03-06 19:22 49 ******************************
0 2017-03-06 20:21 51 ********************************
1 2017-03-06 21:20 51 ********************************
2 2017-03-06 22:19 51 ********************************
3 2017-03-06 23:18 52 *********************************
4 2017-03-07 00:17 53 **********************************
5 2017-03-07 01:16 55 ************************************
6 2017-03-07 02:15 56 *************************************
7 2017-03-07 03:14 57 **************************************
8 2017-03-07 04:13 55 ************************************
9 2017-03-07 05:12 55 ************************************
10 2017-03-07 06:11 55 ************************************
11 2017-03-07 07:10 57 **************************************
12 2017-03-07 08:09 ? -
13 2017-03-07 09:08 43 ************************
14 2017-03-07 10:07 ? -
15 2017-03-07 11:06 48 *****************************
16 2017-03-07 12:05 ? -
17 2017-03-07 13:04 44 *************************
18 2017-03-07 14:03 ? -
19 2017-03-07 15:02 42 ***********************
20 2017-03-07 16:01 ? -
21 2017-03-07 17:00 47 ****************************
22 2017-03-07 17:59 ? -
23 2017-03-07 18:58 50 *******************************
24 2017-03-07 19:57 ? -
25 2017-03-07 20:56 50 *******************************
26 2017-03-07 21:55 ? -
27 2017-03-07 22:54 43 ************************
28 2017-03-07 23:53 ? -
29 2017-03-08 00:52 49 ******************************
30 2017-03-08 01:51 ? -
31 2017-03-08 02:50 36 *****************
32 2017-03-08 03:49 ? -
33 2017-03-08 04:48 47 ****************************
34 2017-03-08 05:47 ? -
35 2017-03-08 06:46 47 ****************************
36 2017-03-08 07:45 ? -
37 2017-03-08 08:44 48 *****************************
38 2017-03-08 09:43 ? -
39 2017-03-08 10:42 22 ***
40 2017-03-08 11:41 45 **************************
41 2017-03-08 12:40 51 ********************************
42 2017-03-08 13:39 ? -
43 2017-03-08 14:38 23 ****
44 2017-03-08 15:37 ? -
45 2017-03-08 16:36 25 ******
46 2017-03-08 17:35 44 *************************
47 2017-03-08 18:34 54 ***********************************
48 2017-03-08 19:33 52 *********************************
49 2017-03-08 20:32 50 *******************************
50 2017-03-08 21:31 50 *******************************
51 2017-03-08 22:30 ? -
52 2017-03-08 23:29 49 ******************************
53 2017-03-09 00:28 50 *******************************
54 2017-03-09 01:27 51 ********************************
55 2017-03-09 02:26 52 *********************************
56 2017-03-09 03:25 52 *********************************
57 2017-03-09 04:24 51 ********************************
... ..( 4 skipped). .. ********************************
62 2017-03-09 09:19 51 ********************************
63 2017-03-09 10:18 52 *********************************

SCT Error Recovery Control command not supported

Device Statistics (GP Log 0x04)
Page Offset Size Value Flags Description
0x01 ===== = = === == General Statistics (rev 1) ==
0x01 0x008 4 165 --- Lifetime Power-On Resets
0x01 0x010 4 1231 --- Power-on Hours
0x01 0x018 6 31210471124 --- Logical Sectors Written
0x01 0x020 6 70848239 --- Number of Write Commands
0x01 0x028 6 20486470386642 --- Logical Sectors Read
0x01 0x030 6 75984325 --- Number of Read Commands
0x01 0x038 6 - --- Date and Time TimeStamp
0x03 ===== = = === == Rotating Media Statistics (rev 1) ==
0x03 0x008 4 2337645339 N-- Spindle Motor Power-on Hours
0x03 0x010 4 2337644452 N-- Head Flying Hours
0x03 0x018 4 3251 --- Head Load Events
0x03 0x020 4 0 --- Number of Reallocated Logical Sectors
0x03 0x028 4 0 --- Read Recovery Attempts
0x03 0x030 4 0 --- Number of Mechanical Start Failures
0x04 ===== = = === == General Errors Statistics (rev 1) ==
0x04 0x008 4 0 --- Number of Reported Uncorrectable Errors
0x04 0x010 4 15 --- Resets Between Cmd Acceptance and Completion
0x05 ===== = = === == Temperature Statistics (rev 1) ==
0x05 0x008 1 52 N-- Current Temperature
0x05 0x010 1 50 N-- Average Short Term Temperature
0x05 0x018 1 49 N-- Average Long Term Temperature
0x05 0x020 1 63 N-- Highest Temperature
0x05 0x028 1 16 N-- Lowest Temperature
0x05 0x030 1 56 N-- Highest Average Short Term Temperature
0x05 0x038 1 14 N-- Lowest Average Short Term Temperature
0x05 0x040 1 52 N-- Highest Average Long Term Temperature
0x05 0x048 1 0 N-- Lowest Average Long Term Temperature
0x05 0x050 4 444 --- Time in Over-Temperature
0x05 0x058 1 55 --- Specified Maximum Operating Temperature
0x05 0x060 4 0 --- Time in Under-Temperature
0x05 0x068 1 13 --- Specified Minimum Operating Temperature
|||_ C monitored condition met
||__ D supports DSN
|___ N normalized value

SATA Phy Event Counters (GP Log 0x11)
ID Size Value Description
0x000a 2 1 Device-to-host register FISes sent due to a COMRESET
0x0001 2 0 Command failed due to ICRC error
0x0003 2 0 R_ERR response for device-to-host data FIS
0x0004 2 0 R_ERR response for host-to-device data FIS
0x0006 2 0 R_ERR response for device-to-host non-data FIS
0x0007 2 0 R_ERR response for host-to-device non-data FIS

Thanks for your message and the information.
However, I do not really see any incompatibilities and especially bad to see a post in "bug report" which is absolutely not a bug.
Can you please tell me why do you think that there is an incompatibility?

As I see on the images, Hard Disk Sentinel not only detects complete status information, complete SMART attributes of the hard disk, but can also help to diagnose the operation of the hard disk in general, allows numerous functions to verify / track status change and reveal any weirdness of the operation of the hard disk itself.
Alone these would confirm that Hard Disk Sentinel completely supports, detects and reports the status of the hard disk correctly.

> but Smartmontools shows no errors logged.

Hard Disk Sentinel performs complete, periodic updates and yes, it is possible that periodically, for example once in each 100 or 1000 detections, it may got error report or problematic response from the device.
As you can see in any tool, if we perform a one-time check, things seem fine (and in 99.99% of the detections, this seems fine in Hard Disk Sentinel too, according the graphs and the details).

So the question is to detect and reveal why the hard disk sometimes reporting other kind of information - and are these real problems or there may be something which causes bad, incomplete response, or so?

So Hard Disk Sentinel can point on such weirdness and can reveal if the drive is sometimes providing weird information - and offers numerous tests to verify the situation, reveal and fix possible issues (for example, see: http://www.hdsentinel.com/faq.php#tests )
This exactly confirms that Hard Disk Sentinel is fully compatible with the device.

> I realize HDS only reports what's recorded in the SMART, but why the sudden increases as if HDS was unable to read the
> SMART at times and then when it could there was a dramatic increase in the attributes value.

This is not really correct. Yes, HDS reads the SMART but if the SMART is somehow corrupted, not readable, it does not use it - but instead it may show problem that the drive is not responding correctly or in worst case the status may be "vanish" as it is better to do not show status at all that showing mis-leading status (which may be possible in other tools).

The "dramatic incrase" is completely independent from HDS or the software attempting to read the self-monitoring SMART information.
The "dramatic incrase" is related to the device itself - just would need to investigate if it is
- related to the hard disk itself, so there are problems, fluctuations, unstable operation of the hard disk drive
- caused by something else, usually power source (power fluctuations, power loss) and/or cables, connections which may sometimes not provide accurate connection.
Things may work MOSTLY (at the times when you run an other tool for a quick check) - but it is possible that sometimes do not.
And if this is true, not only the reported status can be bad - but it is possible that the data can be damaged, corrupted.

And if HDS can detect and increase attention to such situation - I'd not call it "incompatible" but exactly the opposite: the only compatible software which is sensitive enough for such issues.


> One day HDS reported that Hard Drive failure was imminent and health dropped from 100% to 9%,
> but before I could get another drive to transfer the data, HDS showed that the health had been
> restored to 100% and all 7000 pending sectors disappeared without being reallocated.

The question: what indicated these errors? Generally some or more problems can be detected any time: it is not rare that problems may remain undetected for long time (even for months/years) until the problematic area is accessed.
This is why I always recommend intensive testing ( http://www.hdsentinel.com/faq.php#tests ) to reveal issues long before they can cause troubles.
But yes, detection of 7000 pending sectors and then suddenly vanishing - it is more than unusual, so it would be worth to investigate what may have caused this.


> HDS logged that the Power Off Retract Cycle Count decreased between 2/20 and 2/26. How is this possible with an incremental attribute?

Exctremely good question.
However, for this, the manufacturer of the hard disk should be able to tell the answer: how this counter can decrease if it should only increase.
But I do not really see it as problem with Hard Disk Sentinel - but exactly the opposite: it shows that the drive may somehow not stable.

For such issues, the most common cause can be that generally there is an issue with the power source of the drive itself.
Power on retract count usually increases on improper shut down, accidental reset / power loss of the device.
As the graph shows, there were many such events happened in the lifetime of the hard disk and it is possible that at certain points, the hard disk may not able to completely and correctly record the changes and updates.

This may result not only that an older value reported again (so the counter may showed a slight decrease) but also it is possible that the S.M.A.R.T. values may be temporary incorrect.
This could be the reason of the fluctuation and the generally too-big-to-be-true error increase and then decrease.


> Also, why can't HDS incorporate viewing the error log stored on the hard drive like Smartmontools?

There are two main reasons for this:

1) even if it sounds weird, in most cases, it does not give any information, useful details or information about any problems or events.
Even for professional users it does not show any reasons - and many recorded "timeouts" and similar events (which do not indicate
problems) may frighten users and may incorrectly think that there are problems.

2) in many cases (for example in RAID situations, RAID environments where other tools can't access any details, just Hard Disk Sentinel)
it is not possible to access this information at all. It is hard to draw any conclusions from details if they are not reproducible,
for example if a hard disk may show other details (logs) when connected internally or by an USB adapter - or via a RAID controller.

Constantly researching about the possibilities and I can confirm this is almost already completed and available (and may be added in a later version) - but even testing of really failed (or almost failed) drives received to data recovery companies may not show useful information about diagnostics of particular problems or events.
So personally I'm not sure the real value and importance of this - as it may not help too much.

Instead, the constant checking of status, detection and reporting of attribute changes (investigating possible changes, degradations) and especially revealing (by the tests available and sensitive enough for issues) such weird situations, fluctuations are the most important and key factors in determining, revealing and fixing problems.
And this is possible (and maybe only possible) with Hard Disk Sentinel.

I examined carefully the output of your drive provided by the other tool - but exactly confirms the above: it shows absolutely nothing - and even more, shows other, more than weird values which should be never treated as correct.

For example
0x03 0x008 4 2337645339 N-- Spindle Motor Power-on Hours
0x03 0x010 4 2337644452 N-- Head Flying Hours


Personally I'd examine data and power cables. The high number of "Command timeout" value is also interesting, indicates that generally something may be not stable in the operation of the enclosure (not neccessarry the drive itself).

Then I'd perform intensive testing as described at http://www.hdsentinel.com/faq.php#tests
exactly to reveal and stabilize possible problems.

If you prefer, you may use Report menu -> Send test report to developer option any time as then it is possible to check the actual status, situation of the drive. You may do multiple times, for example before/after tests, after possible status change - as then it is possible to compare and "follow" the possible status change.

Thank you for your detailed response. I posed the subject as I question because I wasn't sure why I was seeing the things I asked about. I didn't intend to suggest it was definitely a bug in the software.

As you suggested, I will move the data off and do extensive testing of the drive to determine it's stability before using it again. I'll also try other power supplies because there have been times when it shuts down to sleep and won't wake. I have to remove and replace the power and data cables and then Windows will finally recognize it. Thank you for pointing that the drive's power supply could be causing the increase in Power Off Retract Cycle Count. I hadn't considered that.

I just installed Version 5 of HDS after posting this yesterday, so I'll keep checking it with HDS and submit a report if there continue to be anomalies after trying the other things.

Thank you for your time in responding to this problem.

One other thing with this drive and the information in HDS. Attribute 242 Total LBA Read has been pegged at the top of the scale since a week after I added the drive. There is absolutely no possibility the value is accurate if the scale is MB read. The values for this attribute on my 5TB drive are proportionately increasing with use and are similar in value to attribute 241 Total LBA Written.

Is this because the format of this attribute has changed in the newer Seagate drives or could it indicate corruption of the SMART memory?

Thanks for your attention.

Yes, the graph (and generally the value) seems really very high.

As I checked, no, there is no change in newer Seagate drives about how they represent the total LBA read / written, I just verified this model. It may be possible that your drive has different firmware than I used/tested - but I do not really think it would cause difference there.

So it is possible that the counter got corrupted somehow - and may recorded a problematic value.

Can you please use Report menu -> Send test report to developer option? This way it is possible to check the actual, "raw" response and the raw value as-is provided by the hard disk. The problem is that in decimal conversion things may not be as clearly visible as should, it is harder to see the different parts of the raw attribute which may be interpreted differently.

You may also try sending two consecutive reports - and reading a specific amount of data between them. For example, start Disk menu -> Surface test -> Read test and perform 10% disk scan which should indicate 500 GB read on this 5 TB hard disk. This way it is possible to compare the reports, examine how the counter changed - and this would help to identify what happened - and if there is a problem (for example the hard disk recorded an invalid value) how it may be possible to correct it and display the proper amount of reads - even if have only partial / incorrect response (if possible at all).