[Solved] Intermittent extremely slow write on Toshiba Canvio Basics 2TB

Hello all,

I have a problem I'm hoping someone could help with.

Setup:

Proxmox server with OMV in a VM.

2 External USB3.0 HDD connected to the USB3 ports. Formatted NTFS.

Both drives shared to my windows laptop via SMB.

But problem is identical when drives are directly connected to a Windows laptop via USB.

Problem:

The write speed when copying files sometimes drastically slows down to a couple kb/s and even 0b/s. It stays like that for a long time. And then seems to "wake up" and write at full speed again.

Observations/attempts:

1. At first I thought the (new) HDD was bad because it came in lousy packaging. So I returned it and ordered the same model again from a different store. But it behaves exactly the same.

2. The problem occurs via OMV and shared via SMB. But also when I connected the HDD to my Windows laptop directly via USB. So that rules out OMV or SMB issues. Unless OMV or SMB somehow corrupted the drive or filesystem.

3. I have a feeling it is file related. Because this "slow mode" usually seems to kick in when copying a lot of small files. A WordPress folder for example. I've copied 500GB worth of large video files at a consistent 85MB/s. But after it goes into this "slow mode", also large files don't go fast anymore. The same (large) file will write with a stable 85MB/s from start to finish when it's functioning properly. And in "slow mode" it stays at 0b/s with some jumps to the 200kB/s range. And for a short while (2 seconds) to 5MB/s.

4. Also I noticed in this "slow mode", when you start a file transfer, it starts with 100+MB/s for the first 2 seconds, and then radically drops down to 0. Like a buffer is filled quickly somewhere, but it can't empty the buffer to the drive fast enough.

5. Yesterday evening, I gave up. Anything I tried to copy slowed down to 0 within a couple seconds. I just left it like that for the night (connected, mounted, but idle). The next morning, it wrote half of a 1GB iso at full 85MB/s speed. And then slowed down again.

6. The funny thing is also that while it's in "slow mode", the disk usage according to Windows Task Manager is 100%. When it starts writing fast again, the drive usage actually drops.

7. At some point, I could not get OMV to shutdown or restart anymore. It would hang at "Power Down Reached" or something similar. When I pulled the HDD from the USB port of the proxmox server and connected it to my windows laptop, I could not open the main folder. It said it was corrupted. After running chkdsk /f it found 2 errors and fixed it. And everything was accessible again.

8. During this "slow mode", it also takes FOREVER (10-20s) for the S.M.A.R.T. data to load when I select the drive in the OMV GUI. When working normally its less than a second.

9. I turned off Windows Defender during most of this testing.

Video:

I will attach a screen cap of the copying in a minute

My current state:

I don't know what to try anymore. It can't be hardware, since getting a fluke 2 times in a row from separate stores is almost impossible. It's not OMV, since it's the same directly connected to the laptop.

Did anyone experience something similar before? Why is the disk activity 100% when I'm not doing anything?

Thanks in advance.

Update/Solved:

After more reading I believe I found the problem. The problem is SMR drives are shit by design. And soooo much more shit than I ever imagined. And it's also sneaky.

You format the drive and start using it and everything seems fine. No speed difference to my older 2TB 2.5" CMR drive. But after filling it with a couple 100 gigs, it starts to slow down HARD to almost useless write speed (<5MB/s average for large files). So you don't notice its shit after you used it for a while. SMR drives should be advertised with their "SMR speed", not the maximum achievable speed, in my opinion. It's like buying a car that can supposedly do 150km/h, but then it turned out it can do it for 5min, and then drop back to 30km/h for the rest of the drive... Good luck on the highways.

Also I don't agree with the general opinion that its fine when you use it only for backup. Unless you are fine with the file transfer taking days instead of a couple hours.

The only use case I would advise an SMR drive for is if you really don't care at all about write speed and are fine with 4-5MB/s.

I'll try to return it and get a CMR/PMR drive instead. Unfortunately they seem extinct in the 2.5" size class. Back in 2014, I randomly bought an External 2TB 2.5" HDD for 90EUR and it turned out to be CMR. Why did everyone stop making 2.5" 2TB PMR/CMR drives?

Here are 2 video links of some file copy operations where the problem occurs.

Files are being copied from E:\ HDD to D:\ HDD. As you can see, during slow mode, the source E:\ drive is hardly breaking a sweat while the target drive D:\ is 100%.

The 15MB/s top speed is normal in this case, since both source and target drive are connected to the same USB2.0 bus on my laptop. 15read + 15write = 30MB/s.

1.

2.

OK, I've been reading up on SMR vs CMR drives. It appears mine is a SMR type.

But is it normal to slow down so extremely much while writing large files? I've read about speed slowing down from 100+ to 10MB/s when the regular tracks are full and the drive is forced to write in shingled tracks. But nowhere do I see people getting almost 0 like I am.

Problem found. See update in OP. Case closed. SMR=Shit. Stay far away from it unless you really know what you are getting.

Thanks anyway.

I still can't believe this SMR type is being sold to the regular public just like that. And it's 90% of the 2TB 2.5" market as well. No warning, nothing. You REALLY have to look hard for a "normal" PMR type. Where is EU regulation when you need them...

Hmm,, even the read speed is slow now (drive 60% full). 15MB/s (large files). That should not be the case with SMR, should it? As far as I've been able to find out, read speed should be the same as with normal PMR/CMR drives.

Found this picture on the net, it seems suitable..