Additional HDDs Pool?

[Dice]

One question left: you say two separate machines for main/backup are better option than two separate volumes within one system. If I go with two separate volumes is that a lot worse scenario?

yes.
There is in practice no added risk to run 2 vdevs in one pool compared to 2 pools one vdev each.
You would protect yourself slightly from user-errors that cause ZFS to crack.
The point with RAIDZ2 and SMART, SCRUBS, email notificatinos, checkups on health, is that data should never be compromised on a vdev basis.
However, if you have the same data in 2 machines I would think you are less likely to make the same fatal mistake to both machines at the same time.

Remember, most of the posts where users have "lost all their data" on the forum is related to:
- messing up via CLI thinking they are clever
- not configuring warnings systems
- disregarding error messages
- massive user errors such as not paying attention encryption directives.
- Not checking system stability and burning in drives/RAM prior to committing

Don't be afraid of multiple vdevs in one pool. Think about it, mirrors are ...just that.

 

[Fyodor]

Reading Resources, in partiqular Cyberjock's hardware guide, I've learnt that "If any VDev in a zpool is failed, you will lose the entire zpool with no chance of partial recovery." Reading this statement my conclusions were 1) making more than one VDevs a forced action when expanding existing zpool, because we can't add discs into existing VDev; and 2) for the same number of hard drives two zpools are safer than two VDevs in one zpool... Since I'm not expanding, but re-assembling my machine(s) I was not planning for more that one VDev in zpool. Based on this, plan was making two zpools one VDev each (RAIDZ2 for 7x500GBs and probably RAIDZ1 for 4x3TBs) and either place these zpools at 2 machines one zpools in each, or keep both in one machine. Also, my assumption is that one zpool is arranged as logical drive; while VDevs in one zpool can't be set as onle logical drive each VDev.

If I'm wrong - please correct. Probably I have currently no need to make more than one VDev in each zpool. But when you say "There is in practice no added risk to run 2 vdevs in one pool compared to 2 pools one vdev each" I do not completely understand.

 

[SweetAndLow]

Reading Resources, in partiqular Cyberjock's hardware guide, I've learnt that "If any VDev in a zpool is failed, you will lose the entire zpool with no chance of partial recovery." Reading this statement my conclusions were 1) making more than one VDevs a forced action when expanding existing zpool, because we can't add discs into existing VDev; and 2) for the same number of hard drives two zpools are safer than two VDevs in one zpool... Since I'm not expanding, but re-assembling my machine(s) I was not planning for more that one VDev in zpool. Based on this, plan was making two zpools one VDev each (RAIDZ2 for 7x500GBs and probably RAIDZ1 for 4x3TBs) and either place these zpools at 2 machines one zpools in each, or keep both in one machine. Also, my assumption is that one zpool is arranged as logical drive; while VDevs in one zpool can't be set as onle logical drive each VDev.

If I'm wrong - please correct. Probably I have currently no need to make more than one VDev in each zpool. But when you say "There is in practice no added risk to run 2 vdevs in one pool compared to 2 pools one vdev each" I do not completely understand.

Running multiple pool seems like more of a risk to me. I don't think adding vdevs adds to the risk. During a rebuild you only rebuild the vdev not the pool. So this puts al the risk in one vdev always no matter how many vdevs you have.

Sent from my Nexus 5X using Tapatalk

 

[Tock]

Running multiple pool seems like more of a risk to me. I don't think adding vdevs adds to the risk. During a rebuild you only rebuild the vdev not the pool. So this puts al the risk in one vdev always no matter how many vdevs you have.

Well if one vdev dies your whole pool is done for in your example. In Feodors example he only loses half of his data if one of his vdevs (Pools) dies.

 

[Jailer]

It's a personal choice. Do you want your data spread over 2 pools and have to manage 2 pools or do you want 1 pool to manage?

 

[Fyodor]

Tock, yes, exactly what I meant. Yes during rebuild we touch and put a risk to VDevs, not the pools. But during operation, if my 7x500GB backup pool is two VDevs then dying of one of them destroys entire backup data.
Jailer, if I keep one machine than I assume I need at least two pools, individual logical drive (share) each, one for main array, another for backup. This setup will backup thru mobo bus. If I spread it across two machines, than I suggest one pool each machine, again, main and backup, and backing up thru network.

 

[Jailer]

Yes you can have 2 pools in one machine as you describe and set it up to back one pool up to the other. The only thing it doesn't protect you from is catastrophic failure such as a building fire. Even though your data would be duplicated on the same machine you'll still want an off site backup for your important files.

 

[gpsguy]

Given the difference in drive sizes, I'd buy two more 3TB drives and create a 6x3TB RAIDz2 volume.

6 drives instead of 11, will run cooler. And, you'll have about the same amount of storage, with all of it protected in RAIDz2.

I was not planning for more that one VDev in zpool. Based on this, plan was making two zpools one VDev each (RAIDZ2 for 7x500GBs and probably RAIDZ1 for 4x3TBs)

It's not recommended to create a pool with two different RAIDZ configurations. For example, if you create a RAIDz2 vdev, then the rest of the vdev's also be RAIDz2. In the example of pool consisting of 2 vdevs (1 - RAIDz2 and 1 - RAIDz1), if two drives failed in the RAIDz1 vdev, you'd loose all your data.

 

[SweetAndLow]

Well if one vdev dies your whole pool is done for in your example. In Feodors example he only loses half of his data if one of his vdevs (Pools) dies.

This isn't a counter point. Even if you have a single vdev in the pool, losing one will cause the whole pool to die. Adding more vdevs does not increase the risk of data loss.

Sent from my Nexus 5X using Tapatalk

 

[gpsguy]

While you know it, for the newer users in the thread, mixing vdev types in a pool can increase the risk of data loss.

We often see new users try to extend their pool by adding a single disk to an existing RAIDz2 volume. Should the new single disk die, the pool is gone.

Adding more vdevs does not increase the risk of data loss.

 

[Fyodor]

Hello, Stux, I have a question re your builds. You have 8 x 4TB Seagate NAS-HD in RaidZ2 in your Primary, which gives you about 19,2 TB of available storage assuming 80% limit. But your Backup is 5 x 3TB WD Red/Green RaidZ2 which is 7,2 TB... Do you only backup part of data, or compress this much?

 

[Stux]

Hello, Stux, I have a question re your builds. You have 8 x 4TB Seagate NAS-HD in RaidZ2 in your Primary, which gives you about 19,2 TB of available storage assuming 80% limit. But your Backup is 5 x 3TB WD Red/Green RaidZ2 which is 7,2 TB... Do you only backup part of data, or compress this much?

I only backup the data on the Primary that isn't a backup itself. The key is to understand that some data on the 'primary' is already a backup copy. Much of the 19.2TB is actually used for time machine backups of other work stations on the network. So, that data is a backup already, and is only actually required if the workstations fails, and it is not replicated to the backup system. It might be nice to backup those backups, but I can't really justify it.

Any workstation which has business critical data is also backed up to legacy time capsule backup servers both locally and offsite, maintaining the 3-2-1 rule.

Other data is the primary copy of server data and that gets backed up both to the local backup system and to an offsite backup system, as well as copious snapshots. Yet more data is the primary backup for other servers on the network. Those server backups are not replicated to the backup system, but are replicated offsite.

So, critical data meets the 3-2-1 rule, 3 copies, 2 local on different machines and 1 offsite. All data is backed up at least once.

Primary is at about 70% usage. Will be acquiring another 8x4TB drives for it in the next month or two. Will grow the backup system if/when I need to.

 

[Stux]

OK, got it! Have declined both options. Instead found X10SLM-F / E3-1230v3 system with 4 GB RAM onboard, two extra HDDs and consumer type desk-top case. I will need to add RAM immediately to at least match 8 GB minimum. With this option I can either take two machines main/backup approach and 4 x 3TB HDDs will go to new system to serve as main array, or fit everything into current large Thermaltake ATX case with custom added extra fan and arrange two separate pools for main storage and backup at the same platform. Last choice seems better/easier for home use, but I may be wrong in this. Two HDDs are 500 GB each, so can expand my current 5 x 500 GB machine that is going to be backup. Here is the plan! Is that good enough?

7x500GB would make a nice little RaidZ2 array for your backup system ;)

 

[Fyodor]

Yes, this is what I think of. New 3 TB drives are actualy not new but quite used, so I need to decide how should I arrange a pool. Here are smartctl outputs after long test for all 4:

Code:

Welcome to FreeNAS
[root@freenas] ~# smartctl -a /dev/ada0
smartctl 6.5 2016-05-07 r4318 [FreeBSD 10.3-STABLE amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:	 Western Digital Green
Device Model:	 WDC WD30EZRX-00MMMB0
Serial Number:	WD-WCAWZ0764777
LU WWN Device Id: 5 0014ee 205ec2969
Firmware Version: 80.00A80
User Capacity:	3,000,592,982,016 bytes [3.00 TB]
Sector Sizes:	 512 bytes logical, 4096 bytes physical
Device is:		In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 1.5 Gb/s)
Local Time is:	Tue May  9 13:30:20 2017 MSK
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:  (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:				(50160) 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:		( 482) minutes.
Conveyance self-test routine
recommended polling time:		(   5) minutes.
SCT capabilities:			  (0x3035) SCT Status 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	 0x002f   200   200   051	Pre-fail  Always	   -	   0
  3 Spin_Up_Time			0x0027   150   143   021	Pre-fail  Always	   -	   9466
  4 Start_Stop_Count		0x0032   091   091   000	Old_age   Always	   -	   9613
  5 Reallocated_Sector_Ct   0x0033   200   200   140	Pre-fail  Always	   -	   0
  7 Seek_Error_Rate		 0x002e   200   200   000	Old_age   Always	   -	   0
  9 Power_On_Hours		  0x0032   059   059   000	Old_age   Always	   -	   30402
 10 Spin_Retry_Count		0x0032   100   100   000	Old_age   Always	   -	   0
 11 Calibration_Retry_Count 0x0032   100   100   000	Old_age   Always	   -	   0
 12 Power_Cycle_Count	   0x0032   099   099   000	Old_age   Always	   -	   1953
192 Power-Off_Retract_Count 0x0032   200   200   000	Old_age   Always	   -	   48
193 Load_Cycle_Count		0x0032   144   144   000	Old_age   Always	   -	   169046
194 Temperature_Celsius	 0x0022   129   099   000	Old_age   Always	   -	   23
196 Reallocated_Event_Count 0x0032   200   200   000	Old_age   Always	   -	   0
197 Current_Pending_Sector  0x0032   200   200   000	Old_age   Always	   -	   0
198 Offline_Uncorrectable   0x0030   200   200   000	Old_age   Offline	  -	   0
199 UDMA_CRC_Error_Count	0x0032   200   200   000	Old_age   Always	   -	   0
200 Multi_Zone_Error_Rate   0x0008   200   200   000	Old_age   Offline	  -	   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%	 30378		 -
# 2  Extended offline	Completed without error	   00%	 30247		 -

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.


//////////////////////////////////////////////////////////////////////////////////////////


[root@freenas] ~# smartctl -a /dev/ada1
smartctl 6.5 2016-05-07 r4318 [FreeBSD 10.3-STABLE amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:	 Western Digital Green
Device Model:	 WDC WD30EZRX-00MMMB0
Serial Number:	WD-WCAWZ1452902
LU WWN Device Id: 5 0014ee 25ba5a411
Firmware Version: 80.00A80
User Capacity:	3,000,592,982,016 bytes [3.00 TB]
Sector Sizes:	 512 bytes logical, 4096 bytes physical
Device is:		In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 1.5 Gb/s)
Local Time is:	Tue May  9 13:38:51 2017 MSK
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:  (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:				(52800) 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:		( 507) minutes.
Conveyance self-test routine
recommended polling time:		(   5) minutes.
SCT capabilities:			  (0x3035) SCT Status 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	 0x002f   200   200   051	Pre-fail  Always	   -	   0
  3 Spin_Up_Time			0x0027   152   144   021	Pre-fail  Always	   -	   9375
  4 Start_Stop_Count		0x0032   091   091   000	Old_age   Always	   -	   9317
  5 Reallocated_Sector_Ct   0x0033   200   200   140	Pre-fail  Always	   -	   0
  7 Seek_Error_Rate		 0x002e   200   200   000	Old_age   Always	   -	   0
  9 Power_On_Hours		  0x0032   061   061   000	Old_age   Always	   -	   28815
 10 Spin_Retry_Count		0x0032   100   100   000	Old_age   Always	   -	   0
 11 Calibration_Retry_Count 0x0032   100   100   000	Old_age   Always	   -	   0
 12 Power_Cycle_Count	   0x0032   099   099   000	Old_age   Always	   -	   1878
192 Power-Off_Retract_Count 0x0032   200   200   000	Old_age   Always	   -	   45
193 Load_Cycle_Count		0x0032   179   179   000	Old_age   Always	   -	   64000
194 Temperature_Celsius	 0x0022   127   100   000	Old_age   Always	   -	   25
196 Reallocated_Event_Count 0x0032   200   200   000	Old_age   Always	   -	   0
197 Current_Pending_Sector  0x0032   200   200   000	Old_age   Always	   -	   0
198 Offline_Uncorrectable   0x0030   200   200   000	Old_age   Offline	  -	   0
199 UDMA_CRC_Error_Count	0x0032   200   200   000	Old_age   Always	   -	   0
200 Multi_Zone_Error_Rate   0x0008   200   200   000	Old_age   Offline	  -	   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%	 28791		 -
# 2  Extended offline	Completed without error	   00%	 28660		 -

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.


//////////////////////////////////////////////////////////////////////////////////////////


[root@freenas] ~# smartctl -a /dev/ada2
smartctl 6.5 2016-05-07 r4318 [FreeBSD 10.3-STABLE amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:	 Western Digital Green
Device Model:	 WDC WD30EZRX-00MMMB0
Serial Number:	WD-WCAWZ0719246
LU WWN Device Id: 5 0014ee 2b096f6f7
Firmware Version: 80.00A80
User Capacity:	3,000,592,982,016 bytes [3.00 TB]
Sector Sizes:	 512 bytes logical, 4096 bytes physical
Device is:		In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 1.5 Gb/s)
Local Time is:	Tue May  9 13:39:58 2017 MSK
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:  (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:				(49200) 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:		( 473) minutes.
Conveyance self-test routine
recommended polling time:		(   5) minutes.
SCT capabilities:			  (0x3035) SCT Status 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	 0x002f   200   200   051	Pre-fail  Always	   -	   0
  3 Spin_Up_Time			0x0027   148   142   021	Pre-fail  Always	   -	   9583
  4 Start_Stop_Count		0x0032   091   091   000	Old_age   Always	   -	   9568
  5 Reallocated_Sector_Ct   0x0033   200   200   140	Pre-fail  Always	   -	   0
  7 Seek_Error_Rate		 0x002e   200   200   000	Old_age   Always	   -	   0
  9 Power_On_Hours		  0x0032   059   059   000	Old_age   Always	   -	   30090
 10 Spin_Retry_Count		0x0032   100   100   000	Old_age   Always	   -	   0
 11 Calibration_Retry_Count 0x0032   100   100   000	Old_age   Always	   -	   0
 12 Power_Cycle_Count	   0x0032   099   099   000	Old_age   Always	   -	   1951
192 Power-Off_Retract_Count 0x0032   200   200   000	Old_age   Always	   -	   73
193 Load_Cycle_Count		0x0032   153   153   000	Old_age   Always	   -	   141152
194 Temperature_Celsius	 0x0022   126   104   000	Old_age   Always	   -	   26
196 Reallocated_Event_Count 0x0032   200   200   000	Old_age   Always	   -	   0
197 Current_Pending_Sector  0x0032   200   200   000	Old_age   Always	   -	   0
198 Offline_Uncorrectable   0x0030   200   200   000	Old_age   Offline	  -	   0
199 UDMA_CRC_Error_Count	0x0032   200   200   000	Old_age   Always	   -	   0
200 Multi_Zone_Error_Rate   0x0008   200   200   000	Old_age   Offline	  -	   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%	 30066		 -
# 2  Extended offline	Completed without error	   00%	 29935		 -

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.


///////////////////////////////////////////////////////////////////////////////////////////////////


[root@freenas] ~# smartctl -a /dev/ada3
smartctl 6.5 2016-05-07 r4318 [FreeBSD 10.3-STABLE amd64] (local build)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:	 Western Digital Green
Device Model:	 WDC WD30EZRX-00MMMB0
Serial Number:	WD-WCAWZ1452699
LU WWN Device Id: 5 0014ee 25ba5a37f
Firmware Version: 80.00A80
User Capacity:	3,000,592,982,016 bytes [3.00 TB]
Sector Sizes:	 512 bytes logical, 4096 bytes physical
Device is:		In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS (minor revision not indicated)
SATA Version is:  SATA 3.0, 6.0 Gb/s (current: 1.5 Gb/s)
Local Time is:	Tue May  9 13:40:32 2017 MSK
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:  (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:				(52080) 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:		( 500) minutes.
Conveyance self-test routine
recommended polling time:		(   5) minutes.
SCT capabilities:			  (0x3035) SCT Status 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	 0x002f   200   200   051	Pre-fail  Always	   -	   0
  3 Spin_Up_Time			0x0027   151   141   021	Pre-fail  Always	   -	   9425
  4 Start_Stop_Count		0x0032   091   091   000	Old_age   Always	   -	   9200
  5 Reallocated_Sector_Ct   0x0033   200   200   140	Pre-fail  Always	   -	   0
  7 Seek_Error_Rate		 0x002e   200   200   000	Old_age   Always	   -	   0
  9 Power_On_Hours		  0x0032   061   061   000	Old_age   Always	   -	   28827
 10 Spin_Retry_Count		0x0032   100   100   000	Old_age   Always	   -	   0
 11 Calibration_Retry_Count 0x0032   100   100   000	Old_age   Always	   -	   0
 12 Power_Cycle_Count	   0x0032   099   099   000	Old_age   Always	   -	   1879
192 Power-Off_Retract_Count 0x0032   200   200   000	Old_age   Always	   -	   53
193 Load_Cycle_Count		0x0032   185   185   000	Old_age   Always	   -	   46931
194 Temperature_Celsius	 0x0022   127   101   000	Old_age   Always	   -	   25
196 Reallocated_Event_Count 0x0032   200   200   000	Old_age   Always	   -	   0
197 Current_Pending_Sector  0x0032   200   200   000	Old_age   Always	   -	   0
198 Offline_Uncorrectable   0x0030   200   200   000	Old_age   Offline	  -	   0
199 UDMA_CRC_Error_Count	0x0032   200   200   000	Old_age   Always	   -	   0
200 Multi_Zone_Error_Rate   0x0008   200   185   000	Old_age   Offline	  -	   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%	 28804		 -
# 2  Extended offline	Completed without error	   00%	 28673		 -
# 3  Extended offline	Completed without error	   00%	 28288		 -
# 4  Extended offline	Completed without error	   00%	 28277		 -

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.

 

[Robert Trevellyan]

Nothing scary in the smartctl output, but you should run wdidle3 on those greens to keep the load cycle counts from getting out of hand.

 

[danb35]

Adding more vdevs does not increase the risk of data loss.

Well, yes, it does, but only minimally so. There is a non-zero risk of failure of any vdev. If two vdevs are in separate pools, the failure of the one vdev will not harm the data on the other pool. But if they're in the same pool, the failure of one vdev will result in the loss of data in both. It's incorrect to say that there's no increased risk.

The counterpoint, that I think @Feodor is missing, is that the risk of loss of a properly-maintained vdev is very very small, and the requirement for "proper maintenance" is very minimal. Regular scrubs, SMART tests, and email alerts, and keeping the drive temps under control, should reduce the risk of catastrophic failure to very nearly zero.

 

[Stux]

Such that the greater risk is operator error

 

[danb35]

Such that the greater risk is operator error

Yes, operator error is the much greater risk.

 

[Fyodor]

It might be worth running badblocks -w, which does 4 write/check read passes across the disk (the writes should fix / reallocate) and see how the SMART stats change. Personally I would scrap it. Also, it is a WD Green so unless you have managed to disable the park heads on idle feature and enable time limited error recovery I'd replace it with something more suitable for a NAS.

https://forums.freenas.org/index.php?resources/hardware-recommendations-guide.12/ and its PDF is well worth reading. A lot of work has been put into the recommendations.

I have just changed Intellipark's timing to 300 sec at all 4 drives. Please advice what should I do to enable time limited error recovery?

 

[Dice]

So, critical data meets the 3-2-1 rule, 3 copies, 2 local on different machines and 1 offsite. All data is backed up at least once.

@Feodor Have a look:
https://www.backblaze.com/blog/the-3-2-1-backup-strategy/