Horrible performance after > 1 TB with external 8 TB SMR disk (WD Elements)

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qpio
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Horrible performance after > 1 TB with external 8 TB SMR disk (WD Elements)

Post by qpio »

I am doing my first full backup to this drive:

* Western Digital WD Elements Desktop Hard Drive 8TB USB3

At first, write speed was excellent (above 200 MB/s), and I was not surprised to see a speed drop after two hours. With SMR disks, if I understand correctly, once the non-SMR area (the quick area) has been filled up, the drive has to do internal housekeeping (moving data) while still receiving new data as well.

So I would expect a drop in performance, maybe to 100 MB/s, or maybe 50 MB/s. But this? Write speed is now at ~ 0,1 MB/s steady all day. Before I return these disks (I bought two) Any thoughts?

My other external backup disks (WD My Book 8 TB USB3) have never shown such poor performance.
Screenshot 2021-01-20 at 18.22.06.png
Screenshot 2021-01-20 at 18.08.58.png
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TS-872, TS-870 Pro, TS-459 Pro II, TS-112
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dolbyman
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Re: Horrible performance after > 1 TB with external 8 TB SMR disk (WD Elements)

Post by dolbyman »

complain to the manufacturer then, these disks are probably not meant for hours of sustained writes (so no housekeeping can be done)
qpio
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Re: Horrible performance after > 1 TB with external 8 TB SMR disk (WD Elements)

Post by qpio »

In case anyone is interested to see how SMR works if you hit the non-SMR cache limit:
Screenshot 2021-01-22 at 15.31.41.png
Still searching for alternatives ... it's not easy to find CMR vs. SMR specs for any external USB disks. Tips welcome!
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qpio
Getting the hang of things
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Joined: Wed May 11, 2011 6:51 am

Re: Horrible performance after > 1 TB with external 8 TB SMR disk (WD Elements)

Post by qpio »

After 16 days the backup is still not finished:
HBS3 job 16 days.png
There are some bursts where a reasonable speed of 100-200 Mb/s is achieved. One of those is in the middle, after my qnap lost power due to a UPS failure (ouch). I've experimented a bit with stopping the HBS3 job for 1 or 8 hours, so that the PMR cache on the USB disk can flush itself to SMR. However this does not show any improvements. I am no longer suspecting PMR versus SMR to be an issue here. It appears that the HBS3 software itself is choking, apparently when the number of files is larger than what QNAP was expecting to see. In my case there are 7.584.980 files to be backed up.

I have increased the maximum log size to 1024 MB, as suggested in another thread ("Hybrid Backup RTRR impossibly slow"). Did not help. It has been suggested in that thread that "if HBS is removed the built-in Backup Station returns". If that is true, using backup station could be the solution for me.
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syncthing
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Re: Horrible performance after > 1 TB with external 8 TB SMR disk (WD Elements)

Post by syncthing »

maybe you are much faster on the initial copy to use the console (login via ssh) and copy/rsync it to the USB drive

I don't know if WD has 8TB SMR disks, I only read about Seagate has some 8TB SMR disks;
Does anybody have some recent info about it as I am planning to buy a new USB-HDD of this size for backup?
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