Hello Patrick,
I tried it. But it was not successful.
With "hdparm -W 0" iotop shows 3,3-3,7 M/s write speed, with "hdparm -W 1" it is 9,7-10,3 M/s. And the error message about "ring buffer overflow" stays the same with "-W 0" and the recordings are still broken.
Interesting: I made a good recording yesterday directly onto the SD flash card. When I copy that recording to the USB SSD i can play it back with 700-1100 K/s (iotop) without issue.
Any other idea? Could I configure the flash SD card as cache and automoatically copy the recording to the SSD after it is finished?
Matthias
Am 08.08.2016 um 22:53 schrieb Patrick Boettcher:
On Mon, 8 Aug 2016 22:51:13 +0200 Patrick Boettcher patrick.boettcher@posteo.de wrote:
Hi,
On Mon, 8 Aug 2016 20:30:33 +0200 Matthias Bodenbinder matthias@bodenbinder.de wrote:
Hello Christoph,
based on your feedback I made another test. The USB HD performance seems to be ok (see my other reply). But anyways I made a test with recording directly to the Flash SD card. And that works pretty well. 15 min without issue. So it looks like it is indeed an issue with USB on the Raspberry PI 2. Any idea how to solve that?
It _could_ be the write-cache-flush which saturates the bus and then dramatically decreases I/O of the overall system.
Try
hdparm -W 0 /dev/<partition>
You could also try iotop, which should I/O activity of all processes, maybe there is something going on.
sudo apt install iotop sudo iotop
Thanks,