Hi, I’m new here and need some help! I am reporting this as what I think is a kernel bug, and perhaps this will go through the proper channels. I have had this problem since probably Fedora 7, back in the mid 2000’s. I even recently experienced it on Kubuntu. I now run Windows 7 (10 was the nail in the coffin,) Manjaro, and EndeavourOS on different machines.
This singular problem is preventing me from running linux full time, or recommending it to friends/family.
I am trying to copy 260+ GB of data from a SATA hard drive to either
- An external SATA 2TB hard drive via USB 3.0
- An external 128 GB USB 3.0 flash drive (I know this is too small, I only attempted 116GB of data here)
(Edited usb flash drive capacity after rereading what i wrote. 138gb? lol)
In both cases, transfers slow to a crawl. I’m talking 4MB down to 250KB/s. Not good when trying to move 260 gigs.
The drive they are transferring from is a SATA drive
I am using 3.0 ports
They are both 3.0 devices
I have tried increasing dirty bytes
I have tried copying via Doplhin
I have tried cp command
I have tried rsync
I am running on a Live Manjaro KDE ISO on one of the 3.0 ports
(I also tried it on an a machine with manjaro installed, same effect.)
The same thing always happens, it transfers anywhere from 10-70 GB at ~100MB/s, then progressively slows down until hitting 4MB-250KB/s.
I am not talking about the burst of speed incorrectly reported while filling up RAM or cache, which would be irrelevant due to the 70GB that transferred quickly. I am running a Live ISO on 8 GB of ram.
The reason why I am trying to report this as a kernel bug is because it has always existed (search the web for it,) and unless you switch back to windows you may not notice it.
I know this is a bug because: the first 70 GB of data transferred is complete and intact in a VERY short time (definitely less than 30 minutes.) All files open, All files play, etc etc. I stopped the transfer when it became slow and made sure I could safely detach the drive, meaning the files were transferred. On average I would say it was about 75 MB/s transfer speed.
I restarted rsync, and the remaining 12 hours I waited also copied files, but in the end was about 105 GB of 260 GB total. It bounces between 4 MB and 250KB/s. If you search “Slow USB speed” with “linux,” “ubuntu,” etc, you can find literally hundreds of posts highlighting this problem. The question always goes unanswered. (Except expanding dirty bytes, but that seems to only delay the inevitable.)
It makes no difference whether it is the flash drive or hard drive, both start at the same speed, and slow down to the same speed. If I switch to windows, it works as expected. I can copy all of it in about an hour. But I am trying to do this without windows, so I deleted the data and am retrying over and over.
So to reiterate, windows can transfer all of it in about an hour. So please dont say
“slow speeds is normal for USB drives”
“your USB drive is old”
“your drive is a knockoff” (I have bought one before though lol)
“its the cache filling up”
“5mb/s is good for 3.0”
as those are the usual responses.
This is in no way a stab at Manjaro, as this has existed for almost 20 years at this point.
I really appreciate the work you all do here!
But if anyone can help me it would be greatly, greatly appreciated! I would like to get to the bottom of this 20 year old bug. Thanks in advance!