Seagate 8TB Shingled Drives in UnRAID


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My current hypothesis is that the default spin down time of 15 minutes is not enough for the drive to finish its shingling activity if it's seriously backed up. If the persistent cache is empty then the first 25GB of writes should be fast, shouldn't they? Is there anything I can do to diagnose this issue further?

 

It does not work that way.. "shingling" is a part of a regular write cycle, so its not saved up or something like that.. the drive will never spin down without a completed  write..

 

Yes, but it can store writes temporarily in the persistent cache until it gets a chance to write them to the shingled area. That's what I meant by 'shingling activity'. Obviously it's not going to spin down in the middle of a write but it must be able to pause these housekeeping transfers from the persistent cache to the shingled area when it receives a spin down notification.

 

At 100MB/s it would take 4 minutes to transfer all that data. At 10MB/s it would take 45 minutes. A 15 minute spin down is probably too short to allow the drive to finish it's housekeeping in the worst case.

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Randomly, no. But at a moment of our choosing...

I am posting this to continue my contribution to this thread. As you all know I am a big supporter of these drives for the typical unRAID use case. My bi-directional transfer speeds are rock solid and

Hi All,   From around November 2014 I was thinking of building a new system suite because my requirements outstripped the system I had. For detailed reference please go here: http://lime-technology

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My current hypothesis is that the default spin down time of 15 minutes is not enough for the drive to finish its shingling activity if it's seriously backed up. If the persistent cache is empty then the first 25GB of writes should be fast, shouldn't they? Is there anything I can do to diagnose this issue further?

 

It does not work that way.. "shingling" is a part of a regular write cycle, so its not saved up or something like that.. the drive will never spin down without a completed  write..

 

Yes, but it can store writes temporarily in the persistent cache until it gets a chance to write them to the shingled area. That's what I meant by 'shingling activity'. Obviously it's not going to spin down in the middle of a write but it must be able to pause these housekeeping transfers from the persistent cache to the shingled area when it receives a spin down notification.

 

At 100MB/s it would take 4 minutes to transfer all that data. At 10MB/s it would take 45 minutes. A 15 minute spin down is probably too short to allow the drive to finish it's housekeeping in the worst case.

 

The process you are asking about is called cleaning. This is when the persistent cache is unloaded and bands are rewritten.

 

Drives will spin down whenever asked. The process for cleaning is power fail safe. You don't have to worry about keeping the drive running for cleaning.

 

Turns out 15 minutes is not a bad value. Remember this is 15 minutes with no activity. Cleaning begins within 2 seconds of idle time. A band rewrite takes ~600mS. However if you are pushing the SMR drive with random writes until the persistent cache is full (and random write performance is near 0) it can take an hour+ to clean.

 

 

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Turns out 15 minutes is not a bad value. Remember this is 15 minutes with no activity. Cleaning begins within 2 seconds of idle time. A band rewrite takes ~600mS. However if you are pushing the SMR drive with random writes until the persistent cache is full (and random write performance is near 0) it can take an hour+ to clean.

 

When I got home I paused the Midnight Commander transfer and left it alone until the drives stopped making seeking noises. I've got the case apart so I can feel the vibrations in the disks as well. The drives were still cleaning after 23 minutes but they seemed to be finished when I checked again after another half hour. After I resumed the transfer it went along between 80-100MB/s for the first 18GB and then dropped quickly to 40MB/s. After 65GB it's still going at 35-42MB/s so it seems that it was just backed up because of the short spin down time.

 

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I've had a good dozen drives fail within the first few hours of a preclear (~25% DOA from Newegg until I stopped buying from them).

 

Any idea why one merchandiser would have higher failure rates than another with the same hard drive manufacturer ?

 

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I've had a good dozen drives fail within the first few hours of a preclear (~25% DOA from Newegg until I stopped buying from them).

 

Any idea why one merchandiser would have higher failure rates than another with the same hard drive manufacturer ?

Shipping and handling. I've seen more drives die from mishandling than any other cause, other than plain old age.
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What is the name of the non-shingled ones? Do the WD 8TB drives use SMR tech as well? I need more disks but I dont want the cache thingy part on my drives that might cause problem since I sometimes move around alot of data.

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What is the name of the non-shingled ones? Do the WD 8TB drives use SMR tech as well? I need more disks but I dont want the cache thingy part on my drives that might cause problem since I sometimes move around alot of data.

 

The WD 8TB drives are NOT shingled, and are superb drives.  I just bought 4 of them (not for UnRAID), and they are VERY nice -- sequential reads well over 250MB/s.    They're a bit pricey (~ $320), but well worth it.    They're essentially a slower RPM version of the $550 HGST Ultrastar HE8's [ http://www.newegg.com/Product/Product.aspx?Item=N82E16822145969 ], and like the HGST's they're helium-sealed units.    They run very cool; look exactly like the HGST units (except, of course, for the WD Red sticker); and perform exceptionally well.    I'll definitely use these for my next UnRAID upgrade.

 

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What is the name of the non-shingled ones? Do the WD 8TB drives use SMR tech as well? I need more disks but I dont want the cache thingy part on my drives that might cause problem since I sometimes move around alot of data.

 

The non shingled ones are called "desktop drives", the shingled ones are "archive drives"

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What is the name of the non-shingled ones? Do the WD 8TB drives use SMR tech as well? I need more disks but I dont want the cache thingy part on my drives that might cause problem since I sometimes move around alot of data.

 

The WD 8TB drives are NOT shingled, and are superb drives.  I just bought 4 of them (not for UnRAID), and they are VERY nice -- sequential reads well over 250MB/s.    They're a bit pricey (~ $320), but well worth it.    They're essentially a slower RPM version of the $550 HGST Ultrastar HE8's [ http://www.newegg.com/Product/Product.aspx?Item=N82E16822145969 ], and like the HGST's they're helium-sealed units.    They run very cool; look exactly like the HGST units (except, of course, for the WD Red sticker); and perform exceptionally well.    I'll definitely use these for my next UnRAID upgrade.

 

I have all WD RED drives in my system, really happy with them.. I have now gone for the 8tb Seagate because they are slightly faster read/write wise.. Also its good to keep a mix imho

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The Seagates are likely "slightly faster" due to the 1.33TB density of the platters, vs. 1TB for the 3 or 4TB Reds, and 1.2TB for the 6TB units.    Note that the 8TB Reds also have 1.33TB platters, so it's unlikely they are slower than the Seagates.

 

Doesn't hurt, however, to have a mix of drives, just in case there's a bad batch along the way from one of the major manufacturers -- rare, but does happen.    As I noted, however, the helium-sealed 8TB Reds are effectively just consumer-oriented versions of the HGST Ultrastar units, and should be equally reliable (time will tell - mine are only ~ 3 months old at this point, but I couldn't be happier with their performance).

 

 

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Agree -- not worth the gamble.  (a) You don't know for sure what drive is inside; and (b) once the seal is broken, the warranty is voided.    Granted that if you thoroughly test the drive before removing it, it's likely to be very reliable; but I'd much prefer to have a legit warranty I can depend on.

 

Note also that some external drives are formatted with slightly fewer sectors than the drives sold for internal usage => this isn't a big deal in the amount of storage, but even 1 sector difference means you would not be able to use the drive as parity in a system that had internal drives installed with that extra sector.    There have been several instances of this noted on this forum in the past few months.

 

Bottom line:  I'd simply buy the bare drives.    [i agree it's frustrating that they often price external units below the cost of the bare drives.]

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The Seagates are likely "slightly faster" due to the 1.33TB density of the platters, vs. 1TB for the 3 or 4TB Reds, and 1.2TB for the 6TB units.    Note that the 8TB Reds also have 1.33TB platters, so it's unlikely they are slower than the Seagates.

 

Doesn't hurt, however, to have a mix of drives, just in case there's a bad batch along the way from one of the major manufacturers -- rare, but does happen.    As I noted, however, the helium-sealed 8TB Reds are effectively just consumer-oriented versions of the HGST Ultrastar units, and should be equally reliable (time will tell - mine are only ~ 3 months old at this point, but I couldn't be happier with their performance).

 

They also have a slighly higher rotational speed.. I am basing myself on the comparison stats.. But the main reason is the drive mix to be honoust..

I have build my backup server totally on seagate shingled archive drives, they also function fine.. That is a cost-based decision..

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Agree the Seagates are excellent drives -- I'll use them as well in my next server.    My basic plan is a WD Red for parity, one or two WD Reds for "non-media" storage (stuff that changes a lot ... images of my systems, backups, etc.); and a bunch of Seagate 8TB SMR's for all my essentially static media.

 

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Bottom line:  I'd simply buy the bare drives.    [i agree it's frustrating that they often price external units below the cost of the bare drives.]

 

Ain't that the truth. Seems to make no sense. If they priced the bare drive at LEAST the same as the external units, most NAS folks would be snapping them up rather than us paying through the nose to get a warranty for a bare drive while hoping we never use it. For us, the best outcome is getting several years usage from our drives and we make a conscious decision to retire them and upgrade to a newer, better technology. Solid hardware = more sales from us. Instead, we get the shell game.

 

Garycase - are you using Red PROs or just Reds? I am looking for anyone who has experiences with the PRO versions. (Negative or Positive)

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Since Seagate 8TB SMR are a lower price than the WD 6TB Reds, I use all 8TB SMR in the server that holds backups of my main server, and the 6TB Reds in the main server.

 

That way, I get more backup storage for the $$$, and I get some future-proofing if I upgrade the main server to 8TB drives later.

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Garycase - are you using Red PROs or just Reds? I am looking for anyone who has experiences with the PRO versions. (Negative or Positive)

 

Just the Reds ... I have a bunch of 3TB and 4TB units, and 4 of the 8TB drives.    They've all been exceptionally reliable (NO failures to date, and no reallocated or pending sectors on any of them).

 

I thought about buying a couple of the Pro's for my desktop, but wanted the 8TB capacity -- and that's not offered in a Pro version [i suppose the HGST Ultrastar is effectively the "Pro" version, but it's just more $$ than I was willing to spend).

 

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Garycase - are you using Red PROs or just Reds? I am looking for anyone who has experiences with the PRO versions. (Negative or Positive)

 

Just the Reds ... I have a bunch of 3TB and 4TB units, and 4 of the 8TB drives.    They've all been exceptionally reliable (NO failures to date, and no reallocated or pending sectors on any of them).

 

I thought about buying a couple of the Pro's for my desktop, but wanted the 8TB capacity -- and that's not offered in a Pro version [i suppose the HGST Ultrastar is effectively the "Pro" version, but it's just more $$ than I was willing to spend).

 

Since Seagate 8TB SMR are a lower price than the WD 6TB Reds, I use all 8TB SMR in the server that holds backups of my main server, and the 6TB Reds in the main server.

 

That way, I get more backup storage for the $$$, and I get some future-proofing if I upgrade the main server to 8TB drives later.

 

Have either of you guys used these drives with the new 6.2 beta and done a Parity Check or Rebuild with these drives as Parity in a Dual Parity setup?

 

As you know I do try and do my own testing but I have had a shocking year to date, serious illness, broken arm, death of best friend .... lets just say, I don't think Ill test this soon. Not being Lazy!

 

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Have either of you guys used these drives with the new 6.2 beta and done a Parity Check or Rebuild with these drives as Parity in a Dual Parity setup?

 

If you mean the Seagates speeds are normal in a dual parity setup, same as single parity.

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Have either of you guys used these drives with the new 6.2 beta and done a Parity Check or Rebuild with these drives as Parity in a Dual Parity setup?

 

If you mean the Seagates speeds are normal in a dual parity setup, same as single parity.

 

Yes, sorry, should have specified. Made an assumption based on the thread.

 

Excellent, thank you.

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Below the results of a preclear of a seagate 8TB shingled drive.

 

Device Model:    ST8000AS0002-1NA17Z

Serial Number:    xxxxxxx

LU WWN Device Id: 5 000c50 0908f403f

Firmware Version: AR15

User Capacity:    8,001,563,222,016 bytes [8.00 TB]

Sector Sizes:    512 bytes logical, 4096 bytes physical

Rotation Rate:    5980 rpm

Device is:        Not in smartctl database [for details use: -P showall]

ATA Version is:  ACS-2, ACS-3 T13/2161-D revision 3b

SATA Version is:  SATA 3.1, 6.0 Gb/s (current: 6.0 Gb/s)

Local Time is:    Tue Apr  5 08:28:36 2016 PDT

SMART support is: Available - device has SMART capability.

SMART support is: Enabled

 

 

Preclear Successful^n... Total time 73:43:58^n... Pre-Read time 19:55:32 (111 MB/s)^n... Zeroing time 17:38:39 (125 MB/s)^n... Post-Read time 36:08:27 (61 MB/s)

 

================================================================== 1.15

=                unRAID server Pre-Clear disk /dev/sdc

=              cycle 1 of 1, partition start on sector 1

= Disk Pre-Clear-Read completed                                DONE

= Step 1 of 10 - Copying zeros to first 2048k bytes            DONE

= Step 2 of 10 - Copying zeros to remainder of disk to clear it DONE

= Step 3 of 10 - Disk is now cleared from MBR onward.          DONE

= Step 4 of 10 - Clearing MBR bytes for partition 2,3 & 4      DONE

= Step 5 of 10 - Clearing MBR code area                        DONE

= Step 6 of 10 - Setting MBR signature bytes                    DONE

= Step 7 of 10 - Setting partition 1 to precleared state        DONE

= Step 8 of 10 - Notifying kernel we changed the partitioning  DONE

= Step 9 of 10 - Creating the /dev/disk/by* entries            DONE

= Step 10 of 10 - Verifying if the MBR is cleared.              DONE

= Disk Post-Clear-Read completed                                DONE

Disk Temperature: 31C, Elapsed Time:  73:43:58

========================================================================1.15

== ST8000AS0002-1NA17Z 

== Disk /dev/sdc has been successfully precleared

== with a starting sector of 1

============================================================================

** Changed attributes in files: /tmp/smart_start_sdc  /tmp/smart_finish_sdc

                ATTRIBUTE  NEW_VAL OLD_VAL FAILURE_THRESHOLD STATUS      RAW_VALUE

      Raw_Read_Error_Rate =  114    100            6        ok          74771072

          Seek_Error_Rate =    73    100          30        ok          21528871

        Spin_Retry_Count =  100    100          97        near_thresh 0

        End-to-End_Error =  100    100          99        near_thresh 0

          High_Fly_Writes =    99    100            0        ok          1

  Airflow_Temperature_Cel =    69      77          45        near_thresh 31

      Temperature_Celsius =    31      23            0        ok          31

  Hardware_ECC_Recovered =  114    100            0        ok          74771072

No SMART attributes are FAILING_NOW

0 sectors were pending re-allocation before the start of the preclear.

0 sectors were pending re-allocation after pre-read in cycle 1 of 1.

0 sectors were pending re-allocation after zero of disk in cycle 1 of 1.

0 sectors are pending re-allocation at the end of the preclear,

    the number of sectors pending re-allocation did not change.

0 sectors had been re-allocated before the start of the preclear.

0 sectors are re-allocated at the end of the preclear,

    the number of sectors re-allocated did not change.

root@Tower:/usr/local/emhttp#

 

This was run on:

unraid 6.1.6

Intel® Core™2 Duo CPU E6550 @ 2.33GHz

2GB ram

ibm m1015 it mode

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I finally have one of these.

 

My google foo is failing, what is the difference between a V2 and a V1 of this drive. The adverts all put V2 in description (Seagate Archive V2 8TB 128MB Cache Hard Drive SATA 6Gb/s 5900RPM - OEM) but I can see no information anywhere on what a V1 drive was or how to identify it.

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I finally have one of these.

 

My google foo is failing, what is the difference between a V2 and a V1 of this drive. The adverts all put V2 in description (Seagate Archive V2 8TB 128MB Cache Hard Drive SATA 6Gb/s 5900RPM - OEM) but I can see no information anywhere on what a V1 drive was or how to identify it.

 

V1: ST8000AS0002

V2: ST8000AS0022

 

Differences:

https://lime-technology.com/forum/index.php?topic=47509.0

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