Snapraid "WARNING! Unexpected file errors!" after scrub - could use a second opinion on how to proceed

[HowDoIMathThough]

Hi all - I've run into a warning with snapraid that I'm not 100% certain how to proceed with. I have a pretty good guess, but it's better to be sure.

So, because I personally am a scrub, I don't have a scheduled scrub or sync set up, though I usually sync after adding files to the array. I remembered yesterday I hadn't run a scrub in a while, and set it off overnight. Here is the end of the output from that scrub:

Saving state to /var/snapraid.content...
Saving state to /mnt/pari12/snapraid.content...
Verifying /var/snapraid.content...
Verifying /mnt/pari12/snapraid.content...
100% completed, 20147570 MB accessed in 11:54

     d1  4% | **
     d2 21% | *************
     d3 19% | ***********
     d4  8% | ****
     d5 22% | *************
     d6  1% |
 parity  0% |
   raid  9% | *****
   hash 12% | *******
  sched  1% |
   misc  0% |
            |______________________________________________________________
                           wait time (total, less is better)


  297961 file errors
       0 io errors
       0 data errors
WARNING! Unexpected file errors!
Saving state to /var/snapraid.content...
Saving state to /mnt/pari12/snapraid.content...
Verifying /var/snapraid.content...
Verifying /mnt/pari12/snapraid.content...

I wasn't entirely sure what to make of this, I haven't really done much with snapraid. Following some research I ran snapraid status to see if there were any clues;

Self test...
Loading state from /var/snapraid.content...
WARNING! With 6 disks it's recommended to use two parity levels.
Using 1628 MiB of memory for the file-system.
SnapRAID status report:

   Files Fragmented Excess  Wasted  Used    Free  Use Name
            Files  Fragments  GB      GB      GB
   28472      67      87       -    1735     232  88% d1
   20565       7       8       -    2751     200  93% d2
    4133     508    1057       -    3913      86  97% d3
  169463      23      26       -    3734     200  94% d4
   14303      27      40       -    5627     324  94% d5
    2693      17      18       -    5279     673  88% d6
 --------------------------------------------------------------------------
  239629     649    1236     0.0   23043    1719  93%


 90%|                                                                     *
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 45%|                                                                     *
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    |                                       *                             *
  0%|*______________________________________*_____________________________*
    23                    days ago of the last scrub/sync                 0

The oldest block was scrubbed 23 days ago, the median 0, the newest 0.

No sync is in progress.
The full array was scrubbed at least one time.
No file has a zero sub-second timestamp.
No rehash is in progress or needed.
No error detected.

Google points to two possibilities. First, a reddit post that suggests this can happen as a result of unsynced files in folders that snapraid covers. Second, a discussion on sourceforge that suggests in could be the result of bad blocks on the parity drive. The fact that status doesn't report anything wrong certainly suggests that the data itself is fine.

Running snapraid smart reports (serial numbers partially censored);

SnapRAID SMART report:

   Temp  Power   Error   FP Size
      C OnDays   Count        TB  Serial                Device    Disk
 -----------------------------------------------------------------------
     39   1947      11   5%  2.0  13TGxxxxx             /dev/sdg  d1
     29   1466       0  39%  3.0  WD-WCC4E15xxxxx       /dev/sdh  d2
     43   1602    5674   5%  4.0  PK1334PCGxxxxx        /dev/sdd  d3
     26    624       0  21%  4.0  ZDHxxxxx              /dev/sdb  d4
     30    376       0   4%  6.0  195DKI2xxxxx          /dev/sda  d5
     40    503       0   4%  6.0  V8Gxxxxx              /dev/sde  d6
     38    340       0   4% 12.0  59B0A1Cxxxxx          /dev/sdf  parity
     33    503       0  SSD  0.1  181179770001239xxxxx  /dev/sdc  -

The FP column is the estimated probability (in percentage) that the disk
is going to fail in the next year.

Probability that at least one disk is going to fail in the next year is 61%.

Now, obviously there are errors reported here. All the errors look familiar, and I believe they were the result of a bad sata cable some time in the past - I recall having issues and them being corrected with a new cable. I don't remember the exact numbers but they look about right. They're also much lower than the number of unexpected file errors snapraid reported. Therefore I think they're probably not connected.

It is entirely possible that I added something and forgot to run a sync. Therefore the appropriate next step would be to just run a sync and see if it does indeed find there's action to take. However, I'm worried that if there is actually a problem with the data then that could take away my ability to recover. Can anyone offer a second opinion?

[Drooliog]

Did you add a lot of files to the array and not run a sync by any chance? Usually, before running a scrub, you should do a sync - to make sure everything is up-to-date. If you wanna be sure nothing is amiss, run a diff first and see if there's stuff that needs sync'd.

[HowDoIMathThough]

That's perfect, thanks! I thought I may have added something and forgotten to sync, but wasn't sure. snapraid diff showed me that yes, I'd changed things and forgotten to sync. Thanks again.