Clmcm400 Posted July 21, 2017 Share Posted July 21, 2017 I am trying out unraid for the first time. Just built a 30 drive 21TB array. Took about 17 hours or so to run parity (I was starting from scratch... why was that necessary?). Anyway, its finally up, and I have a drive reporting some errors. It doesn't complete the smart short or extended tests, so I assume its a paper weight. However its still green on the unraid dashboard? Can someone please advise and tell me what to look out for? I already researched the reallocated sector count - too early to tell if that's still climbing and I don't know about the rest. Thanks! A snippet follows: 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 104 099 006 Pre-fail Always - 26087299 3 Spin_Up_Time 0x0003 100 099 085 Pre-fail Always - 0 4 Start_Stop_Count 0x0032 100 100 020 Old_age Always - 639 5 Reallocated_Sector_Ct 0x0033 100 100 036 Pre-fail Always - 7 7 Seek_Error_Rate 0x000f 079 060 030 Pre-fail Always - 86661325 9 Power_On_Hours 0x0032 085 085 000 Old_age Always - 13820 10 Spin_Retry_Count 0x0013 100 100 097 Pre-fail Always - 0 12 Power_Cycle_Count 0x0032 100 037 020 Old_age Always - 622 184 End-to-End_Error 0x0032 100 100 099 Old_age Always - 0 187 Reported_Uncorrect 0x0032 088 088 000 Old_age Always - 12 188 Command_Timeout 0x0032 100 099 000 Old_age Always - 2 189 High_Fly_Writes 0x003a 100 100 000 Old_age Always - 0 190 Airflow_Temperature_Cel 0x0022 066 054 045 Old_age Always - 34 (Min/Max 27/44) 191 G-Sense_Error_Rate 0x0032 100 100 000 Old_age Always - 1 192 Power-Off_Retract_Count 0x0032 100 100 000 Old_age Always - 1 193 Load_Cycle_Count 0x0032 001 001 000 Old_age Always - 2021682 194 Temperature_Celsius 0x0022 034 046 000 Old_age Always - 34 (0 13 0 0 0) 195 Hardware_ECC_Recovered 0x001a 046 042 000 Old_age Always - 26087299 197 Current_Pending_Sector 0x0012 100 100 000 Old_age Always - 4 198 Offline_Uncorrectable 0x0010 100 100 000 Old_age Offline - 4 199 UDMA_CRC_Error_Count 0x003e 200 200 000 Old_age Always - 0 240 Head_Flying_Hours 0x0000 100 253 000 Old_age Offline - 9437 (60 20 0) 241 Total_LBAs_Written 0x0000 100 253 000 Old_age Offline - 884065040 242 Total_LBAs_Read 0x0000 100 253 000 Old_age Offline - 391664078 254 Free_Fall_Sensor 0x0032 100 100 000 Old_age Always - 0 SMART Error Log Version: 1 ATA Error Count: 8 (device log contains only the most recent five errors) CR = Command Register [HEX] FR = Features Register [HEX] SC = Sector Count Register [HEX] SN = Sector Number Register [HEX] CL = Cylinder Low Register [HEX] CH = Cylinder High Register [HEX] DH = Device/Head Register [HEX] DC = Device Command Register [HEX] ER = Error register [HEX] ST = Status register [HEX] Powered_Up_Time is measured from power on, and printed as DDd+hh:mm:SS.sss where DD=days, hh=hours, mm=minutes, SS=sec, and sss=millisec. It "wraps" after 49.710 days. Error 8 occurred at disk power-on lifetime: 13806 hours (575 days + 6 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 -- -- -- -- -- -- -- 40 51 00 ff ff ff 0f Error: UNC at LBA = 0x0fffffff = 268435455 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- 60 00 00 ff ff ff 4f 00 05:01:29.737 READ FPDMA QUEUED 60 00 00 ff ff ff 4f 00 05:01:29.722 READ FPDMA QUEUED 60 00 00 ff ff ff 4f 00 05:01:29.628 READ FPDMA QUEUED 2f 00 01 10 00 00 00 00 05:01:29.627 READ LOG EXT 60 00 00 ff ff ff 4f 00 05:01:26.927 READ FPDMA QUEUED Error 7 occurred at disk power-on lifetime: 13806 hours (575 days + 6 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 -- -- -- -- -- -- -- 40 51 00 ff ff ff 0f Error: UNC at LBA = 0x0fffffff = 268435455 Commands leading to the command that caused the error were: CR FR SC SN CL CH DH DC Powered_Up_Time Command/Feature_Name -- -- -- -- -- -- -- -- ---------------- -------------------- 60 00 00 ff ff ff 4f 00 05:01:26.927 READ FPDMA QUEUED 60 00 00 ff ff ff 4f 00 05:01:26.888 READ FPDMA QUEUED 2f 00 01 10 00 00 00 00 05:01:26.823 READ LOG EXT 60 00 00 ff ff ff 4f 00 05:01:24.164 READ FPDMA QUEUED 60 00 00 ff ff ff 4f 00 05:01:23.460 READ FPDMA QUEUED Quote Link to comment
SSD Posted July 21, 2017 Share Posted July 21, 2017 Not good. You have 7 reallocated sectors and 4 pending sectors. This disk is failing. Quote Link to comment
Clmcm400 Posted July 21, 2017 Author Share Posted July 21, 2017 Ok thanks for confirming. So even though under the disk properties it says "smart check passed" (which is weird because I can't even run the test???) you would replace it. Conventional wisdom Ive read on the forums says if the reallocated sectors don't increase I am probably still good - but if I ever see pending sectors that basically means immediately replace? Quote Link to comment
SSD Posted July 22, 2017 Share Posted July 22, 2017 A pending sector basically means that the firmware has detected a problematic sector that it intends to reallocate on the next write to that sector. But when it actually does a write to that sector, it does a final check to see if if should really reallocate, and sometimes says - its good enough - and doesn't remap it. And unRAID has some pretty cool handling of bad sector reads - if one happens it reconstructs the sector from all the other disks + parity and then WRITES that sector back to the disk with the error. The disk is supposed to remap that sector and now it has the perfect data to write there. This all sounds very good in practice, and if disks would just read the rulebook and play their part, it would work great. But disks tend to work great and have no sector issues, and when sector issues start to crop up, it is more of a symptom of illness than the illness itself. Because despite the drive's remapping and marking sectors for reallocation, the real problem is that some mechanical failure is happening. Maybe the heads aren't being positioned quite accurately. Whatever the reasons, what we know is once a disk that is a bit older, that previously had no reallocated sectors, starts to develop them, they tend to keep developing them. And it is time to replace the disk. Yes, there are tests you can run and ways to try to put a disk back in service, and maybe once in a blue moon it will work for a while, but generally they will disappoint and you'll be looking to replace them. Quote Link to comment
Clmcm400 Posted July 22, 2017 Author Share Posted July 22, 2017 Very thorough. One more question - will unraid alert me to disks that have pending sectors, or should I go and examine each individual disk's smart reports (or worse... rerun individual smart tests across all disks)? Quote Link to comment
JonathanM Posted July 22, 2017 Share Posted July 22, 2017 The larger issue here is that unraid requires perfection from all remaining array drives to correctly rebuild a missing drive. Leaving a questionable drive in the array will bite you at the worst possible moment, at least that's been my personal experience. You may wish to search and read up on how parity does its magic, once you understand that many of the things concerning drive failures, rebuilds and parity sync will become clear. Let me just plant the seed by telling you that the parity disk by itself contains NO sensible data in most cases, and that is the way it has to be. ALL array drives read over their entire capacity combined allow recovery, not just the parity disk and the failed drive, and not just the areas of the disks containing data. I would recommend never having multiple empty drives in an array, only add the drives you need to store data. Even an empty drive failing will put your remaining data in jeopardy. 30 older untested drives all in the array is a recipe for data loss. Quote Link to comment
trurl Posted July 22, 2017 Share Posted July 22, 2017 28 minutes ago, Clmcm400 said: will unraid alert me to disks that have pending sectors It should have already alerted you about those pending sectors if you have notifications configured. Since you asked these questions I assume you have not configured notifications. Quote Link to comment
Clmcm400 Posted July 22, 2017 Author Share Posted July 22, 2017 jonathanm - Understood about using old drives. Unfortunately, I am replacing my full 8 bay synology which is at 32TB currently with this install. I need those old drives to get enough space to complete the migration. Anything that appears as bad from the get go I certainly won't use for the migration... but any drives that appear OK will need to be used. Once that's done, I will rip out my good disks from the synology (higher capacity WD reds) and put those in the unraid array. So this is temporary. trurl - Correct - brand new install and still learning. I will configure. Quote Link to comment
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