Identifying hourly high disk I/O/flushing activity

-TrueNAS 24.04.2.3 on TerraMaster F4-424, 32GB RAM
-boot-pool on NVMe
-2 data pools:
[STORAGE] - 2x 10TB Seagate Ironwolf MIRRORED (sda, sdb)
[SNAPSHOTS] - 2x 1TB WD MIRRORED (sdc, sdd)
-no other vdevs

Is there any way of identifying the cause of this activity? Only happening with the Ironwolf drives. Happens every 20 mins past the hour for close to one minute. Disk I/O is near 100 with the disks writing, seemingly from flushing operation. SMART readouts are OK. No tasks are scheduled to run 20 mins past the hour. No cron jobs, or other scripts that I can think of either. Any logs I could look into? I’d include a screenshot of the netdata chart, but denied…

Thanks!

smartctl -x /dev/sda (output for sdb looks practically identical)

=== START OF INFORMATION SECTION ===
Device Model:     ST10000VN000-3AK101
Serial Number:    XXXXXXX
LU WWN Device Id: 5 000c50 0e927168c
Firmware Version: SC60
User Capacity:    10,000,831,348,736 bytes [10.0 TB]
Sector Sizes:     512 bytes logical, 4096 bytes physical
Rotation Rate:    7200 rpm
Form Factor:      3.5 inches
Device is:        Not in smartctl database 7.3/5528
ATA Version is:   ACS-4 (minor revision not indicated)
SATA Version is:  SATA 3.3, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is:    Mon Oct 21 10:44:31 2024 EDT
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
DSN feature is:   Disabled
ATA Security is:  Disabled, frozen [SEC2]
Write SCT (Get) Feature Control Command failed: scsi error badly formed scsi parameters
Wt Cache Reorder: Unknown (SCT Feature Control command failed)

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

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:                (  559) 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:        ( 876) 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          FLAGS    VALUE WORST THRESH FAIL RAW_VALUE
  1 Raw_Read_Error_Rate     POSR--   080   064   044    -    107095824
  3 Spin_Up_Time            PO----   091   091   000    -    0
  4 Start_Stop_Count        -O--CK   100   100   020    -    7
  5 Reallocated_Sector_Ct   PO--CK   100   100   010    -    0
  7 Seek_Error_Rate         POSR--   068   060   045    -    5961254
  9 Power_On_Hours          -O--CK   100   100   000    -    113
 10 Spin_Retry_Count        PO--C-   100   100   097    -    0
 12 Power_Cycle_Count       -O--CK   100   100   020    -    7
 18 Unknown_Attribute       PO-R--   100   100   050    -    0
187 Reported_Uncorrect      -O--CK   100   100   000    -    0
188 Command_Timeout         -O--CK   100   100   000    -    0
190 Airflow_Temperature_Cel -O---K   065   052   000    -    35 (Min/Max 35/48)
192 Power-Off_Retract_Count -O--CK   100   100   000    -    2
193 Load_Cycle_Count        -O--CK   100   100   000    -    12
194 Temperature_Celsius     -O---K   035   048   000    -    35 (0 21 0 0 0)
197 Current_Pending_Sector  -O--C-   100   100   000    -    0
198 Offline_Uncorrectable   ----C-   100   100   000    -    0
199 UDMA_CRC_Error_Count    -OSRCK   200   200   000    -    0
240 Head_Flying_Hours       ------   100   100   000    -    113 (133 8 0)
241 Total_LBAs_Written      ------   100   253   000    -    3843235248
242 Total_LBAs_Read         ------   100   253   000    -    1391342874
                            ||||||_ 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     R/O    256  Device Statistics log
0x04       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      2  Power Conditions log
0x09           SL  R/W      1  Selective self-test log
0x0a       GPL     R/W      8  Device Statistics Notification
0x0c       GPL     R/O   2048  Pending Defects log
0x10       GPL     R/O      1  NCQ Command Error log
0x11       GPL     R/O      1  SATA Phy Event Counters log
0x13       GPL     R/O      1  SATA NCQ Send and Receive log
0x21       GPL     R/O      1  Write stream error log
0x22       GPL     R/O      1  Read stream error log
0x24       GPL     R/O    768  Current Device Internal Status Data log
0x2f       GPL     R/O      1  Set Sector Configuration
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     160  Device vendor specific log
0xa2       GPL     VS   16320  Device vendor specific log
0xa4       GPL,SL  VS     160  Device vendor specific log
0xa6       GPL     VS     192  Device vendor specific log
0xa8-0xa9  GPL,SL  VS     136  Device vendor specific log
0xab       GPL     VS       1  Device vendor specific log
0xad       GPL     VS      16  Device vendor specific log
0xb1       GPL,SL  VS     160  Device vendor specific log
0xb6       GPL     VS    1920  Device vendor specific log
0xbe-0xbf  GPL     VS   65535  Device vendor specific log
0xc1       GPL,SL  VS       8  Device vendor specific log
0xc3       GPL,SL  VS      24  Device vendor specific log
0xc6       GPL     VS    5184  Device vendor specific log
0xc7       GPL,SL  VS       8  Device vendor specific log
0xc9       GPL,SL  VS       8  Device vendor specific log
0xca       GPL,SL  VS      16  Device vendor specific log
0xcd       GPL,SL  VS       1  Device vendor specific log
0xce       GPL     VS       1  Device vendor specific log
0xcf       GPL     VS     512  Device vendor specific log
0xd1       GPL     VS     656  Device vendor specific log
0xd2       GPL     VS   10256  Device vendor specific log
0xd4       GPL     VS    2048  Device vendor specific log
0xda       GPL,SL  VS       1  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)
Num  Test_Description    Status                  Remaining  LifeTime(hours)  LBA_of_first_error
# 1  Short offline       Completed without error       00%        85         -
# 2  Short offline       Completed without error       00%        56         -

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)
Device State:                        Active (0)
Current Temperature:                    35 Celsius
Power Cycle Min/Max Temperature:     35/48 Celsius
Lifetime    Min/Max Temperature:     21/48 Celsius
Under/Over Temperature Limit Count:   0/12
SMART Status:                        0xc24f (PASSED)
Vendor specific:
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 03 00 00 00 00 00 00 00 00 00 00 00

SCT Temperature History Version:     2
Temperature Sampling Period:         4 minutes
Temperature Logging Interval:        59 minutes
Min/Max recommended Temperature:     10/25 Celsius
Min/Max Temperature Limit:            5/70 Celsius
Temperature History Size (Index):    128 (0)

Index    Estimated Time   Temperature Celsius
   1    2024-10-16 05:22     ?  -
   2    2024-10-16 06:21    21  **
   3    2024-10-16 07:20    38  *******************
   4    2024-10-16 08:19    39  ********************
   5    2024-10-16 09:18    40  *********************
 ...    ..(  8 skipped).    ..  *********************
  14    2024-10-16 18:09    40  *********************
  15    2024-10-16 19:08    39  ********************
  16    2024-10-16 20:07    39  ********************
  17    2024-10-16 21:06    40  *********************
 ...    ..(  2 skipped).    ..  *********************
  20    2024-10-17 00:03    40  *********************
  21    2024-10-17 01:02    39  ********************
 ...    ..(  3 skipped).    ..  ********************
  25    2024-10-17 04:58    39  ********************
  26    2024-10-17 05:57    40  *********************
  27    2024-10-17 06:56    40  *********************
  28    2024-10-17 07:55    42  ***********************
  29    2024-10-17 08:54    42  ***********************
  30    2024-10-17 09:53    40  *********************
 ...    ..(  3 skipped).    ..  *********************
  34    2024-10-17 13:49    40  *********************
  35    2024-10-17 14:48    39  ********************
 ...    ..( 18 skipped).    ..  ********************
  54    2024-10-18 09:29    39  ********************
  55    2024-10-18 10:28    40  *********************
 ...    ..(  3 skipped).    ..  *********************
  59    2024-10-18 14:24    40  *********************
  60    2024-10-18 15:23    41  **********************
  61    2024-10-18 16:22    40  *********************
 ...    ..(  3 skipped).    ..  *********************
  65    2024-10-18 20:18    40  *********************
  66    2024-10-18 21:17    39  ********************
  67    2024-10-18 22:16    39  ********************
  68    2024-10-18 23:15    40  *********************
 ...    ..(  5 skipped).    ..  *********************
  74    2024-10-19 05:09    40  *********************
  75    2024-10-19 06:08    39  ********************
  76    2024-10-19 07:07    40  *********************
 ...    ..(  2 skipped).    ..  *********************
  79    2024-10-19 10:04    40  *********************
  80    2024-10-19 11:03    39  ********************
 ...    ..(  4 skipped).    ..  ********************
  85    2024-10-19 15:58    39  ********************
  86    2024-10-19 16:57    40  *********************
 ...    ..( 12 skipped).    ..  *********************
  99    2024-10-20 05:44    40  *********************
 100    2024-10-20 06:43     ?  -
 101    2024-10-20 07:42    40  *********************
 102    2024-10-20 08:41     ?  -
 103    2024-10-20 09:40    37  ******************
 104    2024-10-20 10:39     ?  -
 105    2024-10-20 11:38    37  ******************
 106    2024-10-20 12:37    44  *************************
 107    2024-10-20 13:36    45  **************************
 108    2024-10-20 14:35    45  **************************
 109    2024-10-20 15:34    46  ***************************
 110    2024-10-20 16:33    45  **************************
 111    2024-10-20 17:32    45  **************************
 112    2024-10-20 18:31     ?  -
 113    2024-10-20 19:30    45  **************************
 114    2024-10-20 20:29     ?  -
 115    2024-10-20 21:28    44  *************************
 116    2024-10-20 22:27     ?  -
 117    2024-10-20 23:26    44  *************************
 118    2024-10-21 00:25    47  ****************************
 119    2024-10-21 01:24    47  ****************************
 120    2024-10-21 02:23    48  *****************************
 121    2024-10-21 03:22    46  ***************************
 122    2024-10-21 04:21    47  ****************************
 123    2024-10-21 05:20    39  ********************
 124    2024-10-21 06:19    35  ****************
 ...    ..(  3 skipped).    ..  ****************
   0    2024-10-21 10:15    35  ****************

SCT Error Recovery Control:
           Read:     70 (7.0 seconds)
          Write:     70 (7.0 seconds)

Device Statistics (GP Log 0x04)
Page  Offset Size        Value Flags Description
0x01  =====  =               =  ===  == General Statistics (rev 1) ==
0x01  0x008  4               7  ---  Lifetime Power-On Resets
0x01  0x010  4             113  ---  Power-on Hours
0x01  0x018  6      3843235248  ---  Logical Sectors Written
0x01  0x020  6         9415182  ---  Number of Write Commands
0x01  0x028  6      1391342466  ---  Logical Sectors Read
0x01  0x030  6         1801331  ---  Number of Read Commands
0x01  0x038  6               -  ---  Date and Time TimeStamp
0x03  =====  =               =  ===  == Rotating Media Statistics (rev 1) ==
0x03  0x008  4             113  ---  Spindle Motor Power-on Hours
0x03  0x010  4             113  ---  Head Flying Hours
0x03  0x018  4              12  ---  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
0x03  0x038  4               0  ---  Number of Realloc. Candidate Logical Sectors
0x03  0x040  4               2  ---  Number of High Priority Unload Events
0x04  =====  =               =  ===  == General Errors Statistics (rev 1) ==
0x04  0x008  4               0  ---  Number of Reported Uncorrectable Errors
0x04  0x010  4               0  ---  Resets Between Cmd Acceptance and Completion
0x04  0x018  4               0  -D-  Physical Element Status Changed
0x05  =====  =               =  ===  == Temperature Statistics (rev 1) ==
0x05  0x008  1              35  ---  Current Temperature
0x05  0x010  1              40  ---  Average Short Term Temperature
0x05  0x018  1               -  ---  Average Long Term Temperature
0x05  0x020  1              48  ---  Highest Temperature
0x05  0x028  1              30  ---  Lowest Temperature
0x05  0x030  1              41  ---  Highest Average Short Term Temperature
0x05  0x038  1              39  ---  Lowest Average Short Term Temperature
0x05  0x040  1               -  ---  Highest Average Long Term Temperature
0x05  0x048  1               -  ---  Lowest Average Long Term Temperature
0x05  0x050  4               0  ---  Time in Over-Temperature
0x05  0x058  1              70  ---  Specified Maximum Operating Temperature
0x05  0x060  4               0  ---  Time in Under-Temperature
0x05  0x068  1               5  ---  Specified Minimum Operating Temperature
0x06  =====  =               =  ===  == Transport Statistics (rev 1) ==
0x06  0x008  4               5  ---  Number of Hardware Resets
0x06  0x010  4               0  ---  Number of ASR Events
0x06  0x018  4               0  ---  Number of Interface CRC Errors
0xff  =====  =               =  ===  == Vendor Specific Statistics (rev 1) ==
0xff  0x010  7               0  ---  Vendor Specific
0xff  0x018  7               0  ---  Vendor Specific
                                |||_ C monitored condition met
                                ||__ D supports DSN
                                |___ N normalized value

Pending Defects log (GP Log 0x0c)
No Defects Logged

SATA Phy Event Counters (GP Log 0x11)
ID      Size     Value  Description
0x000a  2            2  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

Seagate FARM log (GP Log 0xa6) supported [try: -l farm]

Hey @andywantsitnow

Try attaching your netdata graph image now, that will hopefully help illuminate some things.

When are your snapshots scheduled, and what’s the workload you’re running on your TrueNAS system (SMB, NFS, iSCSI, Apps?)

Snapshot is only taken for one dataset, every wednesday at 0300. Workload is light. SMB for files, occasional media stream. Qbittorrent (v5.0.0) from the GitHub - truenas/charts: TrueNAS SCALE Apps Catalogs & Charts catalog runs as an app… and that’s where i found the issue.

It has a setting “Save resume data interval” set to 60 mins. If i changed it to 3, the disk I/O issue occurs as anticipated: every 3 minutes. Now i suppose for 200 or so running t*rrents there’s a fair amount of data to save (but they’re mostly seeding so should have no new data). Now to figure out a way to mitigate, because i don’t recall it happening prior to changing the setup to 2x10TB ironwolves for the STORAGE dataset- i can hear them chugging away every hour. Old setup was 4x1TB random SKU of WD drives in RAID1z.

Perhaps this can be tagged Apps, not performance anymore?

So tinkered with qBittorrent settings. 2 hours after the last event (15:00), there was no spike. Disk completed ext IO operation metric also appears to have generally reduced overall as well.

Settings i changed for reference via webui:
[Connection]
Peer connection protocol=TCP

[Advanced]
-Resume data storage type=SQLite
-Save resume data interval=120 mins
-File pool size=1000
-Disk cache=32
-Disk IO read/write mode= both Disable OS cache

Will reboot and observe.