Shutdown problem with an USB memory stick as ZFS cache device

[Ronald Klop]

On Wed, 17 Jul 2013 10:27:09 +0200, Maurizio Vairani  
<maurizio.vairani at cloverinformatica.it> wrote:

> Hi all,
>
>
> on a Compaq Presario laptop I have just installed the latest stable
>
>
> #uname -a
>
> FreeBSD presario 9.2-PRERELEASE FreeBSD 9.2-PRERELEASE #0: Tue Jul 16  
> 16:32:39 CEST 2013     root at presario:/usr/obj/usr/src/sys/GENERIC  amd64
>
>
> For speed up the compilation I have added to the pool, tank0,  a SanDisk  
> memory stick as cache device with the command:
>
>
> # zpool add tank0 cache /dev/da0
>
>
> But when I shutdown the laptop the process will halt with this screen  
> shot:
>
>
> http://www.dump-it.fr/freebsd-screen-shot/2f9169f18c7c77e52e873580f9c2d4bf.jpg.html
>
>
> and I need to press the power button for more than 4 seconds to switch  
> off the laptop.
>
> The problem is always reproducible.

Does sysctl hw.usb.no_shutdown_wait=1 help?

Ronald.