WD Elements 4TB - performance drop after re-partitioning

WD External Drives WD Portable Drives
1

Performance dropped after re-partitioning a brand new WD Elements 4TB (type: 2620 USB-HDD).

Why does performance drop when you re-format and how can it be prevented?

The recommended WD Quick Formatter states:

Once the WD Quick Formatter is finished reformatting the drive, the drive will only have one partition. This is necessary in order to optimize the performance of the drive.

Why is it necessary to have one partition in order to have better performance?

Performance before re-partitioning (brand new out of store state):

Random Write 4KiB (Q= 1,T= 1) : 6.181 MB/s

CrystalDiskMark 6.0.0 x64 (C) 2007-2017 hiyohiyo
Crystal Dew World : https://crystalmark.info/

  • MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]

  • KB = 1000 bytes, KiB = 1024 bytes

    Sequential Read (Q= 32,T= 1) : 32.038 MB/s
    Sequential Write (Q= 32,T= 1) : 25.363 MB/s
    Random Read 4KiB (Q= 8,T= 8) : 4.091 MB/s [ 998.8 IOPS]
    Random Write 4KiB (Q= 8,T= 8) : 3.397 MB/s [ 829.3 IOPS]
    Random Read 4KiB (Q= 32,T= 1) : 4.179 MB/s [ 1020.3 IOPS]
    Random Write 4KiB (Q= 32,T= 1) : 6.072 MB/s [ 1482.4 IOPS]
    Random Read 4KiB (Q= 1,T= 1) : 4.090 MB/s [ 998.5 IOPS]
    Random Write 4KiB (Q= 1,T= 1) : 6.181 MB/s [ 1509.0 IOPS]

    Test : 50 MiB [G: 0.0% (0.2/3726.0 GiB)] (x5) [Interval=5 sec]
    Date : 2021/07/30 10:35:39
    OS : Windows 10 Professional [10.0 Build 19041] (x64)

Performance after re-partitioning:

Random Write 4KiB (Q= 1,T= 1) : 4.798 MB/s

CrystalDiskMark 6.0.0 x64 (C) 2007-2017 hiyohiyo
Crystal Dew World : https://crystalmark.info/

  • MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]

  • KB = 1000 bytes, KiB = 1024 bytes

    Sequential Read (Q= 32,T= 1) : 32.173 MB/s
    Sequential Write (Q= 32,T= 1) : 25.631 MB/s
    Random Read 4KiB (Q= 8,T= 8) : 4.091 MB/s [ 998.8 IOPS]
    Random Write 4KiB (Q= 8,T= 8) : 4.251 MB/s [ 1037.8 IOPS]
    Random Read 4KiB (Q= 32,T= 1) : 4.171 MB/s [ 1018.3 IOPS]
    Random Write 4KiB (Q= 32,T= 1) : 4.528 MB/s [ 1105.5 IOPS]
    Random Read 4KiB (Q= 1,T= 1) : 4.088 MB/s [ 998.0 IOPS]
    Random Write 4KiB (Q= 1,T= 1) : 4.798 MB/s [ 1171.4 IOPS]

    Test : 50 MiB [R: 0.0% (0.2/3260.2 GiB)] (x5) [Interval=5 sec]
    Date : 2021/08/02 10:05:16
    OS : Windows 10 Professional [10.0 Build 19041] (x64)

I could’t use the recommended WD Quick Formatter, because I needed an NTFS partition for Windows 10 backups and an EXT4 partition for Linux backup. So I had to split the drive up into two partitions myself.

Here is how I re-partitioned
  1. Under Windows 10: first clear the drive:

  • Enter the Command Prompt window. In the Command window type diskpart and hit Enter.

  • Type diskpart and press Enter

  • Type select disk x and press Enter (x = disk # from Disk Management)

  • Type clean and press Enter

  • A new line will display DiskPart Succeeded in cleaning the disk message. The Command Prompt window can be closed

  • Go to Disk Management and right click the Disk which shows a red, down arrow, this should be the same disk. Select Initialize Disk

  • An Initialize Disk dialog box will open. Select the GPT radio button, and click OK

  • Right click the now Unallocated drive and select New Simple Volume

  • The drive is now ready to use on Windows (performing a nong quick format takes 50 hours +)

  1. Under Linux open gparted, select the remaining space and create an EXT4 partition with it.

When I check after re-partitioning, then I get the following results back:

CHKDSK (Windows) reports: 4096 bytes in each allocation unit

C:\Windows\system32>chkdsk r:
The type of the file system is NTFS.
Volume label is Backup.

WARNING! /F parameter not specified.
Running CHKDSK in read-only mode.

Stage 1: Examining basic file system structure …
256 file records processed.
File verification completed.
Phase duration (File record verification): 54.43 milliseconds.
0 large file records processed.
Phase duration (Orphan file record recovery): 0.86 milliseconds.
0 bad file records processed.
Phase duration (Bad file record checking): 0.46 milliseconds.

Stage 2: Examining file name linkage …
278 index entries processed.
Index verification completed.
Phase duration (Index verification): 30.64 milliseconds.
0 unindexed files scanned.
Phase duration (Orphan reconnection): 1.73 milliseconds.
0 unindexed files recovered to lost and found.
Phase duration (Orphan recovery to lost and found): 0.64 milliseconds.
0 reparse records processed.
0 reparse records processed.
Phase duration (Reparse point and Object ID verification): 5.63 milliseconds.

Stage 3: Examining security descriptors …
Security descriptor verification completed.
Phase duration (Security descriptor verification): 78.30 milliseconds.
11 data files processed.
Phase duration (Data attribute verification): 2.35 milliseconds.

Windows has scanned the file system and found no problems.
No further action is required.

3338472 MB total disk space.
52464704 KB in 7 files.
76 KB in 13 indexes.
0 KB in bad sectors.
170535 KB in use by the system.
65536 KB occupied by the log file.
3287071 MB available on disk.

  **4096 bytes in each allocation unit**.

854649087 total allocation units on disk.
841490259 allocation units available on disk.
Total duration: 177.74 milliseconds (177 ms).

parted (Linux) reports: Sector size (logical/physical): 512B/4096B, Microsoft reserved partition not aligned: 34s % 2048s != 0s

$ sudo parted /dev/sdd
GNU Parted 3.3
Using /dev/sdd
Welcome to GNU Parted! Type ‘help’ to view a list of commands.
(parted) p
Model: WD Elements 2620 (scsi)
Disk /dev/sdd: 4001GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:

Number Start End Size File system Name Flags
1 17,4kB 16,8MB 16,8MB Microsoft reserved partition msftres
2 16,8MB 3501GB 3501GB ntfs Basic data partition msftdata
3 3501GB 4001GB 500GB ext4 Basic data partition

(parted) align-check opt 3
3 aligned
(parted) align-check opt 2
2 aligned
(parted) align-check opt 1
1 not aligned: 34s % 2048s != 0s
(parted)

Freaking Windows creates a Microsoft reserved partition unasked for, which doesn’t show up in Windows diskmanagement. Furtermore it’s unaligned according to Linux’ parted (the NTFS and EXT4 partitions are aligned).
Can the unaligned Microsoft reserved partition do any harm?
Can one select the Sector size (logical/physical) for and USB-HDD alike SSD drives?
Why is there a difference between NTFS and EXT4 in sector size reported?

2

The reserved partition is marked as in use. Linux is not built to be 100% Windows aware of file systems etc.

In short the two partitions should be fine as each handles a separate need.

3

@Vegan

So why is performance (on the NTFS partition) down after re-partitioning?

4

probably due to alignment problems with partitions

5

@vegan
Please read before you hit reply.
The NTFS partition is aligned and so is the EXT4 partition.
The only partition that is not aligned is the unasked for Microsoft reserved partition.

Regarding the Microsoft reserved partition. It appears it’s only filling up the space between the first available sector (s = bytes) and the first MByte boundary, which otherwise would be empty/lost space and can now still be used for data store of formerly hidden sectors.

Explanation why parted aligns at MByte boundaries

Parted is just being overly conservative. The usual practice these days is to align partitions on 1MiB (2048-sector) boundaries because this works on Advanced Format disks, on certain type of RAID setups that require alignment, and on most SSDs. For an Advanced Format disk, so long as the alignment is on a multiple of 8, you’re fine, and 2048 is a multiple of 8. The lost disk space is puny.
[itectec.com]

Hidden sectors on GPT disks:
certain software components used hidden sectors of the disk for data storage purposes. For example, the Logical Disk Manager (LDM), on dynamic disks, stores metadata in a 1 MB area at the end of the disk which is not allocated to any partition.
[Wikipedia]

Because the NTFS partition is aligned, alignment should not be the problem.

Is there a knowledgeable person who can explain why WD states:

What is the reason that performance degrades when the Elements drive is not formatted with the WD Quick Formatter into one partition?
What lurks in the WD Elements drive in order to make such a statement?

Why does performance drop when you re-format and how can it be prevented?

6

A full format of the NTFS 3.5 TB partition took 53 hours.
on the WD Elements 4TB.
It boils down to a formatting speed of 18KB per second on an empty disk.
It reported 0 bad sectors.

7

Now the ghost is out of the box. The culprit seems to be Device-Managed Shingled Magnetic Recording (DMSMR).

I did a lot of reading and investigating and as it turns out my WD Elements 4TB external USB drive contains a covert SMR disk. This was nowhere to be found on the box nor any spec sheet. WD promised to be up front about where they use SMR, but they were not about their WD Elements 4TB external drive and are covertly shipping SMR disks in their Elements line.

How did I find out? Analyze your disk with CrystalDiskInfo.

My WD Elements 4TB box carries a sticker: WDBU6Y0040BBK-EA (on sticker on the box)
CrystalDiskInfo reports:

Enclosure : WD Elements 2620 USB Device (V=1058, P=2620, sa1)
Model : WDC WD40NDZW-11A8JS1

When I search on the model then I find:
WD40NDZW-xxMR8Sx/xxA8JSx 4TB (4/8) ::
“Not For Resale” (5400RPM, 128MB cache, USB 3.0 interface, Advanced Format, Shingled Magnetic Recording, 15mm z-height)
[source]

There you have it, you’ve bought an SMR disk without knowing it.

Now WD has a lot of explaining to do.

  1. Why is performance down by 1/3 after re-partitioning and re-formatting for random writes?
  2. Is the disk after a full format under the impression that it’s full, and will performance be down the drain because it is only doing 256MB zoned block rewrites?
  3. Does alignment have any meaning in Device-Managed Shingled Magnetic Recording (DMSMR)?
  4. Does bad block checking (full format) have any meaning in DMSMR?
  5. What happens when you unplug after safe hardware eject? (there was an unknown blinking patters going on after safe eject, which I now think might have been garbage management, buffered writes by the internal drive management software). Is it now corrupted?
  6. What are the blinking states of the drive (there is no explanation in the short manual to be found).
  7. What is the longevity of data stored on an SMR drive (vs a PMR drive)?
  8. How can one partition into multiple partitions and format without loosing performance?
  9. How to manage the drive for optimal performance
  10. How to configure the drive for optimal usage under Linux
  11. It is complicated and new firmware. Are there any firmware updates (will you get them if there are any)?

Can anybody show me to:

  • a proper manual?
  • a decent spec sheet about the drive ( WD40NDZW-11A8JS1 )?
  • an in depth explanation about their DMSMR implementation

With SMR there are a lot of unanswered questions. Furthermore SMR has ZERO benefits for the user over PMR (but it does have performance and reliability downsides). Are there any WD Elements 4TB drives with PMR disks inside? Ask yourself do you want to have all these uncertainties with your precious data storage?

1 Like
9

Now I have the drive in use for a while.
It is disturbing how slow the drive can be.
Performance is unpredictable.
Opening a file can be slow (seconds) or fast, there is no telling in advance.
It does a lot of internal workings.
Might it be failing or is this normal behavior for an SMR drive???
Can WD answer the questions, please?

1 Like