# Question About Drive in a Software RAID-5

## Bigun

So I've got a three drive RAID-5 array.  Yesterday I copied several gigabytes of data over and was maintaining about 85 MB/s transfer speed.  Today, I moves about 9 more, and noticed the speed dropped to about 12 MB/s.  I looked over at the server and noticed one of the drive lights stayed lit the entire time.  I ran the smartstl -a command on the drive and it took about 30 seconds to extract all the data.  Is this drive starting to "circle the drain"?

```
=== START OF INFORMATION SECTION ===

Model Family:     SAMSUNG SpinPoint F2 EG

Device Model:     SAMSUNG HD154UI

Serial Number:    S1XWJ1KZ213847

LU WWN Device Id: 5 0024e9 00302519c

Firmware Version: 1AG01118

User Capacity:    1,500,301,910,016 bytes [1.50 TB]

Sector Size:      512 bytes logical/physical

Device is:        In smartctl database [for details use: -P show]

ATA Version is:   ATA/ATAPI-7, ATA8-ACS T13/1699-D revision 3b

Local Time is:    Sun Aug 21 03:58:36 2016 EDT

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:                (18808) 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:        (   2) minutes.

Extended self-test routine

recommended polling time:        ( 314) minutes.

Conveyance self-test routine

recommended polling time:        (  33) minutes.

SCT capabilities:              (0x003f) SCT Status supported.

                                        SCT Error Recovery Control supported.

                                        SCT Feature Control supported.

                                        SCT Data Table supported.

SMART Attributes Data Structure revision number: 16

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   100   100   051    Pre-fail  Always       -       0

  3 Spin_Up_Time            0x0007   063   063   011    Pre-fail  Always       -       11950

  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       110

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

  7 Seek_Error_Rate         0x000f   100   100   051    Pre-fail  Always       -       0

  8 Seek_Time_Performance   0x0025   100   100   015    Pre-fail  Offline      -       0

  9 Power_On_Hours          0x0032   089   089   000    Old_age   Always       -       55649

 10 Spin_Retry_Count        0x0033   100   100   051    Pre-fail  Always       -       0

 11 Calibration_Retry_Count 0x0012   100   100   000    Old_age   Always       -       0

 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       110

 13 Read_Soft_Error_Rate    0x000e   100   100   000    Old_age   Always       -       0

183 Runtime_Bad_Block       0x0032   100   100   000    Old_age   Always       -       0

184 End-to-End_Error        0x0033   100   100   000    Pre-fail  Always       -       0

187 Reported_Uncorrect      0x0032   100   100   000    Old_age   Always       -       1

188 Command_Timeout         0x0032   100   100   000    Old_age   Always       -       0

190 Airflow_Temperature_Cel 0x0022   077   039   000    Old_age   Always       -       23 (Min/Max 17/26)

194 Temperature_Celsius     0x0022   076   039   000    Old_age   Always       -       24 (3 38 27 17 0)

195 Hardware_ECC_Recovered  0x001a   100   100   000    Old_age   Always       -       4111713209

196 Reallocated_Event_Count 0x0032   100   100   000    Old_age   Always       -       0

197 Current_Pending_Sector  0x0012   100   100   000    Old_age   Always       -       0

198 Offline_Uncorrectable   0x0030   100   100   000    Old_age   Offline      -       0

199 UDMA_CRC_Error_Count    0x003e   100   100   000    Old_age   Always       -       0

200 Multi_Zone_Error_Rate   0x000a   100   100   000    Old_age   Always       -       0

201 Soft_Read_Error_Rate    0x000a   100   100   000    Old_age   Always       -       0

SMART Error Log Version: 1

No Errors Logged

SMART Self-test log structure revision number 1

No self-tests have been logged.  [To run self-tests, use: smartctl -t]

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.
```

----------

## frostschutz

Although this SMART does not look too bad, this disk has "Auto Offline Data Collection: Disabled." and never run a single selftest.

In the future you should set up smartmontools to do disk monitoring and run regular selftests.

For now, do for all your disks:

```

smartctl --offlineauto=on /dev/sdx

smartctl -t long /dev/sdx # this takes a while

smartctl -a /dev/sdx # to check selftest progress and other values again

```

Also check dmesg for obvious error messages?

If any errors/doubts come up about this drive, add a fourth drive to the system, add it as a spare to the array and then use `mdadm --replace`

If you do not run tests on your arrays / disks, you will not notice read errors in time and risk premature death of your RAID array.

If you do not have a backup, make one...

----------

## NeddySeagoon

Bigun,

Things like

```
[415753.356757] ata1.00: configured for UDMA/133

[415753.356834] sd 0:0:0:0: [sda] Unhandled sense code

[415753.356838] sd 0:0:0:0: [sda]  Result: hostbyte=0x00 driverbyte=0x08

[415753.356843] sd 0:0:0:0: [sda]  Sense Key : 0x3 [current] [descriptor]

[415753.356850] Descriptor sense data with sense descriptors (in hex):

[415753.356854]         72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00 

[415753.356866]         bd dd ff 50 

[415753.356872] sd 0:0:0:0: [sda]  ASC=0x11 ASCQ=0x4

[415753.356877] sd 0:0:0:0: [sda] CDB: cdb[0]=0x28: 28 00 bd dd fe d8 00 01 70 00

[415753.356888] end_request: I/O error, dev sda, sector 3185442640

[415753.356938] ata1: EH complete

[415753.843004] raid5_end_read_request: 16 callbacks suppressed

[415753.843013] md/raid:md2: read error corrected (8 sectors at 3169441616 on sda3)
```

in dmesg are a very bad sign.

This drive died, another in the same raid set died 15 min later.

----------

## Bigun

dmesg isn't showing anything too daunting.  Running a self-test on the offending drive now, waiting on results.

----------

## Bigun

 *frostschutz wrote:*   

> If you do not have a backup, make one...

 

Nightly and offsite.  I do not rely on RAID as backup.  See my backup rig here.

----------

## Bigun

Also, on a side note.  I've ran the command to turn on offline data collection:

```
# smartctl --offlineauto=on /dev/sda

smartctl 6.4 2015-06-04 r4109 [i686-linux-4.4.6-gentoo] (local build)

Copyright (C) 2002-15, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF ENABLE/DISABLE COMMANDS SECTION ===

SMART Automatic Offline Testing Enabled every four hours.
```

However:

```
=== 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.
```

----------

## Bigun

Test completed:

```
# smartctl -a /dev/sda

smartctl 6.4 2015-06-04 r4109 [i686-linux-4.4.6-gentoo] (local build)

Copyright (C) 2002-15, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===

Model Family:     SAMSUNG SpinPoint F2 EG

Device Model:     SAMSUNG HD154UI

Serial Number:    S1XWJ1KZ213847

LU WWN Device Id: 5 0024e9 00302519c

Firmware Version: 1AG01118

User Capacity:    1,500,301,910,016 bytes [1.50 TB]

Sector Size:      512 bytes logical/physical

Device is:        In smartctl database [for details use: -P show]

ATA Version is:   ATA/ATAPI-7, ATA8-ACS T13/1699-D revision 3b

Local Time is:    Sun Aug 21 19:14:00 2016 EDT

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:                (18808) 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:        (   2) minutes.

Extended self-test routine

recommended polling time:        ( 314) minutes.

Conveyance self-test routine

recommended polling time:        (  33) minutes.

SCT capabilities:              (0x003f) SCT Status supported.

                                        SCT Error Recovery Control supported.

                                        SCT Feature Control supported.

                                        SCT Data Table supported.

SMART Attributes Data Structure revision number: 16

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   100   100   051    Pre-fail  Always       -       0

  3 Spin_Up_Time            0x0007   063   063   011    Pre-fail  Always       -       11950

  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       110

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

  7 Seek_Error_Rate         0x000f   100   100   051    Pre-fail  Always       -       0

  8 Seek_Time_Performance   0x0025   100   100   015    Pre-fail  Offline      -       10891

  9 Power_On_Hours          0x0032   089   089   000    Old_age   Always       -       55664

 10 Spin_Retry_Count        0x0033   100   100   051    Pre-fail  Always       -       0

 11 Calibration_Retry_Count 0x0012   100   100   000    Old_age   Always       -       0

 12 Power_Cycle_Count       0x0032   100   100   000    Old_age   Always       -       110

 13 Read_Soft_Error_Rate    0x000e   100   100   000    Old_age   Always       -       0

183 Runtime_Bad_Block       0x0032   100   100   000    Old_age   Always       -       0

184 End-to-End_Error        0x0033   100   100   000    Pre-fail  Always       -       0

187 Reported_Uncorrect      0x0032   100   100   000    Old_age   Always       -       1

188 Command_Timeout         0x0032   100   100   000    Old_age   Always       -       0

190 Airflow_Temperature_Cel 0x0022   074   039   000    Old_age   Always       -       26 (Min/Max 17/27)

194 Temperature_Celsius     0x0022   075   039   000    Old_age   Always       -       25 (3 38 28 17 0)

195 Hardware_ECC_Recovered  0x001a   100   100   000    Old_age   Always       -       2121425378

196 Reallocated_Event_Count 0x0032   100   100   000    Old_age   Always       -       0

197 Current_Pending_Sector  0x0012   100   100   000    Old_age   Always       -       0

198 Offline_Uncorrectable   0x0030   100   100   000    Old_age   Offline      -       0

199 UDMA_CRC_Error_Count    0x003e   100   100   000    Old_age   Always       -       0

200 Multi_Zone_Error_Rate   0x000a   100   100   000    Old_age   Always       -       0

201 Soft_Read_Error_Rate    0x000a   100   100   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%     55664         -

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.

```

----------

## frostschutz

Not sure what the issue is with the auto offline data collection, some drives don't support it but yours claims it does.

Nothing horrible seems to have appeared in the selftest... it passed, and reallocated/pending/uncorrectable is still 0.

So at least according to the drive's internal diagnostics it seems to be fine.

----------

## Bigun

 *frostschutz wrote:*   

> Not sure what the issue is with the auto offline data collection, some drives don't support it but yours claims it does.
> 
> Nothing horrible seems to have appeared in the selftest... it passed, and reallocated/pending/uncorrectable is still 0.
> 
> So at least according to the drive's internal diagnostics it seems to be fine.

 

Ok then, I have backups just in case anyway.  Good to know.

----------

## NeddySeagoon

Bigun,

Maybe a failing SATA data cable, or SATA port on the motherboard.

Internally, the drive looks ok.

----------

## Bigun

Something else may be going on, see here.

----------

