> I found today that tapdisk2 (at least on the latest 4.0-testing/unstable
> and latest pv_ops) is causing data corruption for Windows guests; I can
> see this by copying a few thousand files to another folder inside the
> guest, totalling a bit more than a GB, then running "fc" to check for
> differences (I tried with and without GPLPV). That's obviously a huge
> deal in production (and an even bigger deal than crashes), so in the
> short term, I may have to switch back to the uglier, crashier file:
> setup. I've been trying to find a workaround for the corruption all day
> without much luck.

That's disturbing. It might be worth trying to drop the number of VCPUs in dom0 to 1 and then try to repro.

BTW: for production use I'd currently be strongly inclined to use the XCP 2.6.32 kernel. 

Ian