Re: USB Disk Stalls on -current

From: Graham Perrin <grahamperrin_at_gmail.com>
Date: Mon, 07 Feb 2022 04:02:16 UTC
On 06/02/2022 17:14, Sean Bruno wrote:

> … the clanking/grinding sound of the spinning rust on my desk 
> completely stops, the encoding of the video files stops (so its 
> waiting for a read to complete)…

On 06/02/2022 19:02, Sean Bruno wrote:

> … assuming that I have a fairly dodgy USB device, as the pauses seem 
> to correspond to this from CAM being emitted:
>
> Feb  6 11:56:43 alice kernel: (da0:umass-sim1:1:0:0): READ(10). CDB: 
> 28 00 36 69 02 6e 00 00 80 00
> Feb  6 11:56:43 alice kernel: (da0:umass-sim1:1:0:0): CAM status: CCB 
> request completed with an error
> Feb  6 11:56:43 alice kernel: (da0:umass-sim1:1:0:0): Retrying 
> command, 2 more tries remain
>
> Things resume after this is emitted, but there is a substantial 
> (multiple minutes) pause here. …

Yep, for a pause of that length (without a logged exhaustion) I'd 
suspect the hard disk drive.

Over the years, I've seen 'CCB request completed with an error' often 
enough, and in various situations, with _good_ media e.g. 
<https://pastebin.com/knzQE6Y3>, to get a sense (for myself) of whether 
there's a marginal cable, marginal port at the computer, marginal port 
at the drive, or some combination of those three things.

Can you get S.M.A.R.T. data?

An extended self-test might not expose an issue that becomes evident 
with sustained _writes_ (although I note your opening post comment about 
waiting for a read to complete).

HTH
Graham