Re: USB Disk Stalls on -current

grarpamp <grarpamp@gmail.com> wrote:

> Yes, some USB hw is very flaky,
> but ZFS can work great on these...

For what it's worth, I have had for 2.5 years, tracking stable, a NAS hanging
off a single NUC usb port, with 14 hard disks, 12 of which are used for 2 ZFS,
spools, of two 3X2 mirror spools.

Albeit, I'm using USB3

During heavy writes, I often get:

[1429164] (da10:umass-sim10:10:0:0): WRITE(16). CDB: 8a 00 00 00 00 02 04 39 b2 80 00 00 01 00 00 00
[1429164] (da10:umass-sim10:10:0:0): CAM status: CCB request completed with an error
[1429164] (da10:umass-sim10:10:0:0): Retrying command, 14 more tries remain

, but with no errors or timeouts. I scrub regularly etc.

It rarely has to attempt a retry more than once (although I did bump
"kern.cam.da.retry_count" up to 15 a while back while dealing with another
issue, and never changed it back)

I only get about 300MB/s maximum on file reads though, but the current USB
daisychaining I use isn't ideal. (Each raw disk individually give 150MB/s)

The only issue I have is occasionally the main USB hub craps out, and all
the disks disappear for a few seconds. When it recovers, and the OS sees
the disks again, things remain weird until a reboot.

cheers, Jamie