Re: Stubdom and blktap

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

Yang, Xiaowei wrote:

> Recently we had a try of stubdom, whose general status is good.
> 
> One issue we found is with aio/sync blktap as backend, disk performance
> is obviously slower, and there are some IDE kernel error messages (like
> irq timeout) at boot time.

I'll try to reproduce the problem, thanks for reporting it.

> Another issue (not stubdom specific) comes from blktap's support for
> QCOW image which is based on a backing file. We never tried this
> configure before. The root cause is that in tdqcow_get_parent_id(), the
> backing file is hard-coded to be QCOW type and tdqcow_validate_parent()
> also presumes it, though the backing file is a raw image normally. With
> the image type set correctly and a good method for image validation,
> QCOW works.
> 

I am not sure to understand what the issue is exactly: there is no image
format guessing using blktap, the user is supposed to specify correctly
the format in the VM configuration file.