External USB drive write speed

Hi Zynthianers and happy new year!

I was working on recording a sound to close my previous topic when I got into troubles. After 1 min of recording, the sound was becoming very bad like missing a lot of samples and also not all the record was taken in account. I have investigated a bit what was going on and found a solution that seems nice to integrate in the system.

To record, I saw that a shell script is the wrapper:

So I launched it manually from the shell and discover that after som time I was having what is called overruns in the jack_capture binary project.

I did some speed test on my external USB drive with dd tool (which is USB 3, connected to a USB 3 port from the Raspberry 4). I was getting 400 kbps of write speed… After digging a bit on raspberry forums, I found this article that gave me the solution:

Basically I had to remove the sync option in /etc/usbmount/usbmount.conf. After this I got 24 MBps write speed and no more overrun problems with jack_capture tool.

@jofemodo, something already known / discussed? I use the latest stable build ISO with all zynthian soft up to date.

As I saw in the shell script there is a sync command at the end so no worry about data losses, I might think that reduced read write accesses and linux RAM buffering gave me a good result.

Check this topic… There are maybe a few things in there

Somebody having similar problems there?
I would add this option to the default config, but i would like to have more feedback about this issue.

@zguig, please open an issue on github and we will address the issue in a proper way.


Issue opened!

I found this note in the package usbmount:

The “sync” option may not be a good choice to use with flash drives, as #
it forces a greater amount of writing operating on the drive. This makes #
the writing speed considerably lower and also leads to a faster wear out #
of the disk.

And guess what! I am using a flash USB key :wink: