Record buffer warning

[tommigara]

Hi,
I am encountering a problem specifically at the second recording of the day (each recording is 30 minutes long): the recording stops with the message 'record buffer warning' (see picture).

I am recording from a 16 channels electrode, board v2.2 rev3, GUI v1.0.2 and I have 32 gb of ram and windows 11. The signal chain includes acquisition board -> recording node -> bandpass -> lfp viewer

Thank you in advance for your help.
Best,
Tommaso

[anjaldoshi]

Hi @tommigara,

If the disk writing speed is slower than the rate of incoming data, the Record Node will eventually run out of buffer space. You can monitor this using the buffer indicator for each stream in the Record Node.

When the buffer exceeds 90% capacity, the Record Node automatically stops data acquisition to ensure all files close gracefully and prevent data loss.

Could you try recording to a different drive to see if that resolves the issue? Several factors can slow down write speeds and cause buffers to fill up faster, including I/O contention, background OS activities like Windows Update, indexing, and antivirus scans, especially if you’re recording to the C: drive where the OS is installed. Additionally, low disk space and drive age can also contribute to this issue.

If the issue persists after switching drives, let me know and we can investigate other potential bottlenecks in your recording setup.

[tommigara]

Hi @anjaldoshi,
Thank you for your quick answer. Ok, I will try to change drive!
I still have a doubt: why does this happen only at the end of the second recording and the first one finished without problems?
Best,
Tommaso

[anjaldoshi]

That’s a good question.

A few possible explanations:

• File system or OS write cache — Windows can defer some writes, so the second recording might start before the cached data from the first session has fully written to disk, briefly increasing I/O latency.
• Disk indexing or antivirus scans — these often run right after a file closes and can momentarily slow disk access when the next recording begins.

You could also try waiting 1–2 minutes between recordings or restarting the GUI after the first one to see if that prevents the issue?

[tommigara]

I wait at least 5 minutes after starting the second recording but I will pay attention to background activities to see if something changes after ending the first one. I wil also try restarting the gui and I will post an update.
Best,
Tommaso

[anjaldoshi]

That'd be really helpful!

One more thing to check: could you open Task Manager and monitor disk usage under the Performance tab during both recordings?

Compare the disk activity and transfer rates between the two recordings. This should help reveal if any background processes are interfering with write performance during the second run.

[tommigara]

Hi,
I tried directly with another drive and the problem seems disappeared. On the new disk both recording stay around 5-7% of disk usage, there seem to be no differences. The data rate in the GUI is around 1.67 MB/s in both recording. (I didn't check on the old disk as I did only two recordings)
On the original disk I was also writing the data coming from a camera so that might have created the issue.
Thank you!
Best,
Tommaso