Re: Possible zpool online, resilvering issue

From: Ultima <ultima1252_at_gmail.com>
Date: Wed, 10 Aug 2016 21:52:03 -0400
> A new transaction group (TXG) is created at LEAST every
> vfs.zfs.txg.timeout (defaults to 5) seconds.

> f you offline a drive for hours or more, it must have all blocks with a
> 'birth time' newer than the last transaction that was recorded on the
> offlined drive replayed to catch that drive up to the other drives in
> the pool.

> As long as you have enough redundancy, the checksum errors can be
> corrected without concern.

> In the end, the checksum errors can be written off as being caused by
> the bad hardware. After you finish the scrub and everything is OK, do:
> 'zpool clear poolname', and it will reset all of the error and checksum
> counts to 0, so you can track if any more ever show up.

Thanks Allan, can always count on you for crystal clear answers =]. I'm
surprised tho that it would be concluded as bad hardware(assuming you mean
hd?). Just seems like its too much of a coincidence. I always ran zpool
clear each time after the resilver/scrub was completed.


> Perhaps on or more of the drives running out of Realloc Sectors?
> I had once a case where smartctl showed no issues but zfs scrubbing showed
> a defect, some weeks later smartctl was showing some reallocated sectors
> and one week later the HD was out of spare sectors.

> Have you already tested every single HD for smart issues?


Smartd is set to run a short test weekly on Tuesday Thursday and Saturday.
Extended test is performed weekly on Tuesday an hour after the short test.
This occurs on all 24 drives. A scrub is performed once per month on
Saturday an hour after the short test.

5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail  Always
  -       0

This is the value of Reallocated sectors on all the drives(I think this is
the normal value?). This drives smart looks like the worst of the lot.

=== 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: (  592) 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: ( 491) minutes.
Conveyance self-test routine
recommended polling time: (   2) minutes.
SCT capabilities:       (0x50bd) SCT Status supported.
SCT Error Recovery Control 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          FLAG     VALUE WORST THRESH TYPE      UPDATED
 WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x000f   072   063   044    Pre-fail  Always
    -       20189561
  3 Spin_Up_Time            0x0003   091   091   000    Pre-fail  Always
    -       0
  4 Start_Stop_Count        0x0032   100   100   020    Old_age   Always
    -       188
  5 Reallocated_Sector_Ct   0x0033   100   100   010    Pre-fail  Always
    -       0
  7 Seek_Error_Rate         0x000f   092   085   030    Pre-fail  Always
    -       1802626788
  9 Power_On_Hours          0x0032   081   081   000    Old_age   Always
    -       17457
 10 Spin_Retry_Count        0x0013   100   100   097    Pre-fail  Always
    -       0
 12 Power_Cycle_Count       0x0032   100   100   020    Old_age   Always
    -       158
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   099   000    Old_age   Always
    -       65537
189 High_Fly_Writes         0x003a   100   100   000    Old_age   Always
    -       0
190 Airflow_Temperature_Cel 0x0022   055   045   045    Old_age   Always
In_the_past 45 (Min/Max 34/51)
191 G-Sense_Error_Rate      0x0032   100   100   000    Old_age   Always
    -       0
192 Power-Off_Retract_Count 0x0032   100   100   000    Old_age   Always
    -       157
193 Load_Cycle_Count        0x0032   100   100   000    Old_age   Always
    -       867
194 Temperature_Celsius     0x0022   045   055   000    Old_age   Always
    -       45 (0 22 0 0 0)
195 Hardware_ECC_Recovered  0x001a   053   011   000    Old_age   Always
    -       20189561
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

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  Extended offline    Completed without error       00%     17423
  -
# 2  Short offline       Completed without error       00%     17412
  -
# 3  Short offline       Completed without error       00%     17340
  -
# 4  Short offline       Completed without error       00%     17293
  -
# 5  Extended offline    Completed without error       00%     17261
  -
# 6  Short offline       Completed without error       00%     17245
  -
# 7  Short offline       Completed without error       00%     17173
  -
# 8  Short offline       Completed without error       00%     17125
  -
# 9  Extended offline    Completed without error       00%     17101
  -
#10  Short offline       Completed without error       00%     17084
  -
#11  Short offline       Completed without error       00%     17012
  -
#12  Short offline       Completed without error       00%     16964
  -
#13  Extended offline    Completed without error       00%     16927
  -
#14  Short offline       Completed without error       00%     16916
  -
#15  Short offline       Completed without error       00%     16916
  -
#16  Short offline       Completed without error       00%     16844
  -
#17  Short offline       Completed without error       00%     16805
  -
#18  Extended offline    Completed without error       00%     16775
  -
#19  Short offline       Completed without error       00%     16757
  -
#20  Short offline       Completed without error       00%     16685
  -
#21  Short offline       Completed without error       00%     16637
  -

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.

On Wed, Aug 10, 2016 at 2:56 PM, olli hauer <ohauer_at_gmx.de> wrote:

> On 2016-08-04 07:22, Ultima wrote:
> > Hello,
> >
> > I recently had some issue with a PSU and ran several scrubs on a pool
> with
> > around 35T. Random drives would drop and require a zpool online, this
> found
> > checksum errors. (as expected) However, after all the scrubs I ran, I
> think
> > I may have found a bug with zpool online resilvering process.
> >
> > 24 disks total, 4 vdevs raidz2 (6 drives each).
> >
> > Before this next part... I had a backup PSU, however it was also going
> bad
> > and waiting for RMA. The current one seemed to be dieing but ran fine
> with
> > less drives. So I decided I would run the server short 4 drives.
> >
> > Started by offline(or already removed from psu) 4 drives from different
> > vdevs, then ran a scrub to verify everything. Many sum errors were
> present
> > on some of the drives, but this was expected due to faulty psu. Then
> > offlined 4 different drives and onlined the other 4 and scrubbed once
> > again. After resilver, again, many sum errors on these drives as
> expected.
> >
> > After the scrub completed, I decided to offline 4 different drives, then
> > online the ones that were out of pool for awhile. During the resilver,
> > checksum errors were once again found. I was surprised due to the recent
> > scrub, So I decided to run another scrub, and it found even more checksum
> > errors on these recently onlined drives. I didn't think much about it,
> > however after the replacement PSU arrived, I onlined all the drives out
> of
> > pool and again, resilver had checksum errors as well as another scrub
> with
> > more sum errors.
> >
> > Is this issue known? Is it common for a scrub to be required after
> onlining
> > a disk that was out of pool for some time?
> >
> > The drives are ST4000NM0033, and until recent have never had a single
> > checksum error in they're lifetime.(at least with zfs)
> > FreeBSD S1 12.0-CURRENT FreeBSD 12.0-CURRENT #19 r303224: Sat Jul 23
> > 10:41:12 EDT 2016
> > root_at_S1:/usr/src/head/obj/usr/src/head/src/sys/MYKERNEL-NODEBUG
> >  amd64
> >
> >
> > Sorry for the wall of text, but I hope this helps in tracking down this
> > possible bug.
> >
>
> Perhaps on or more of the drives running out of Realloc Sectors?
> I had once a case where smartctl showed no issues but zfs scrubbing showed
> a defect, some weeks later smartctl was showing some reallocated sectors
> and one week later the HD was out of spare sectors.
>
> Have you already tested every single HD for smart issues?
>
> --
> olli
>
Received on Wed Aug 10 2016 - 23:52:05 UTC

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