Uncorrectable parity/CRC error

[FreeNasJoe]

I'm seeing the following error messages continuously in the console messages area in the footer of the freeNAS web GUI:


Dec -- --:31:59 freenas (ada6:ahcich6:0:0:0): Retrying command
Dec -- --:31:59 freenas (ada6:ahcich6:0:0:0): WRITE_FPDMA_QUEUED. ACB: 61 68 90 ab c1 40 0e 00 00 00 00 00
Dec -- --:31:59 freenas (ada6:ahcich6:0:0:0): CAM status: Uncorrectable parity/CRC error
Dec -- --:31:59 freenas (ada6:ahcich6:0:0:0): Retrying command
Dec -- --:32:03 freenas (ada6:ahcich6:0:0:0): WRITE_FPDMA_QUEUED. ACB: 61 e0 20 13 45 40 08 00 00 00 00 00
Dec -- --:32:03 freenas (ada6:ahcich6:0:0:0): CAM status: Uncorrectable parity/CRC error
Dec -- --:32:03 freenas (ada6:ahcich6:0:0:0): Retrying command
Dec -- --:32:03 freenas (ada6:ahcich6:0:0:0): WRITE_FPDMA_QUEUED. ACB: 61 30 30 9a 09 40 02 00 00 00 00 00
Dec -- --:32:03 freenas (ada6:ahcich6:0:0:0): CAM status: Uncorrectable parity/CRC error
Dec -- --:32:03 freenas (ada6:ahcich6:0:0:0): Retrying command


ada6 is a 256GB SSD used for storing jails.

I saw from another similar post the suggestion to run the command:

smartctl -a -q noserial /dev/ada6

Here is the output of this command:


smartctl 6.5 2016-05-07 r4318 [FreeBSD 11.0-STABLE amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family: Samsung based SSDs
Device Model: Samsung SSD 850 PRO 256GB
Firmware Version: EXM02B6Q
User Capacity: 256,060,514,304 bytes [256 GB]
Sector Size: 512 bytes logical/physical
Rotation Rate: Solid State Device
Form Factor: 2.5 inches
Device is: In smartctl database [for details use: -P show]
ATA Version is: ACS-2, ATA8-ACS T13/1699-D revision 4c
SATA Version is: SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Wed Dec -- --:26:33 2017 MST
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: (0x00) Offline data collection activity
was never started.
Auto Offline Data Collection: Disabled.
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: (0x53) SMART execute Offline immediate.
Auto Offline data collection on/off support.
Suspend Offline collection upon new
command.
No 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: ( 2) minutes.
Extended self-test routine
recommended polling time: ( 133) minutes.
SCT capabilities: (0x003d) SCT Status supported.
SCT Error Recovery Control supported.
SCT Feature Control supported.
SCT Data Table supported.

SMART Attributes Data Structure revision number: 1
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAG VALUE WORST THRESH TYPE UPDATED WHEN_FAILED RAW_VALUE
5 Reallocated_Sector_Ct 0x0033 100 100 010 Pre-fail Always - 0
9 Power_On_Hours 0x0032 099 099 000 Old_age Always - 717
12 Power_Cycle_Count 0x0032 099 099 000 Old_age Always - 13
177 Wear_Leveling_Count 0x0013 099 099 000 Pre-fail Always - 4
179 Used_Rsvd_Blk_Cnt_Tot 0x0013 100 100 010 Pre-fail Always - 0
181 Program_Fail_Cnt_Total 0x0032 100 100 010 Old_age Always - 0
182 Erase_Fail_Count_Total 0x0032 100 100 010 Old_age Always - 0
183 Runtime_Bad_Block 0x0013 100 100 010 Pre-fail Always - 0
187 Uncorrectable_Error_Cnt 0x0032 100 100 000 Old_age Always - 0
190 Airflow_Temperature_Cel 0x0032 074 064 000 Old_age Always - 26
195 ECC_Error_Rate 0x001a 200 200 000 Old_age Always - 0
199 CRC_Error_Count 0x003e 083 083 000 Old_age Always - 16835
235 POR_Recovery_Count 0x0012 099 099 000 Old_age Always - 10
241 Total_LBAs_Written 0x0032 099 099 000 Old_age Always - 1663635028

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% 287 -

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
255 0 65535 Read_scanning was never started
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.


I think this says the SSD (ada6) is physically okay meaning this is a data corruption problem and not a hardware problem. Is this correct?

I'd appreciate any suggestions on how to go about clearing / correcting the error.

 

[Johnnie Black]

199 CRC_Error_Count 0x003e 083 083 000 Old_age Always - 16835

Likely a very bad SATA cable, try replacing it and see it this attribute stops increasing.

 

[FreeNasJoe]

Replacing the SATA cable seems to have done the trick. I puzzle over how a once good cable suddenly goes very bad given that it resides inside a NAS box - a stable and benign environment for such a cable.

:) Thanks for the suggestion Johnnie Black.;)

 

[joeschmuck]

I puzzle over how a once good cable suddenly goes very bad given that it resides inside a NAS box - a stable and benign environment for such a cable.

Trust me, it happens. I had a hard time believing it too when it happened to me and the box was in the basement where no one could or would touch it yet it happened.

 

[pnc]

Thank you so much for this. in my case a poorly seated cable. There were occasions of very poor performance I never understood because nas is in basement and monitor is usually turned off. Today I was updating bios and noticed crc errors. one query, instant fix. those are the problems i like!

 

[joeschmuck]

one query, instant fix. those are the problems i like!

Agreed!