Xen project Mailing List

2017年1月20日上午1:41，"Roger Pau Monné" <roger.pau@xxxxxxxxxx>写道：

On Tue, Jan 17, 2017 at 10:06:07PM +0800, G.R. wrote:
> On Tue, Jan 17, 2017 at 7:57 PM, Kuba <kuba.0000@xxxxx> wrote:
>
> > W dniu 2017-01-16 o 17:06, G.R. pisze:
> >
> >> Hi all,
> >> I'm trying out the storage driver domain feature
> >>
> >
> > Hi
> >
> > A while ago, with a great deal of help from Roger Pau Monné, I managed to
> > use FreeBSD domU as storage driver domain to provide storage for other
> > domUs.
> >
> > The main difference is that it didn't require any network-based protocol
> > (iSCSI etc.) between the domains.
> >
> > Typically your domU's frontend driver is connected to a block device
> > inside dom0 via dom0's backend driver. But Xen has the ability to connect
> > your domU's frontend driver directly to the backend driver of another domU.
> > In short, you can create a storage driver domain, create a block device
> > inside it (e.g. a zvol) and than create another domU using this block
> > device directly, just as if it was provided by dom0.
> >
> > Here you can find the steps that should get you started. It was a while
> > ago and required to apply a patch to Xen; I don't know what's its status
> > right now, but since FreeNAS is based on FreeBSD, it might be worth to take
> > a look:
> >
> > https://lists.xenproject.org/archives/html/xen-users/2014-08/msg00003.html
> >
> Hi Kuba,
> The information you provided sounds fairly interesting! Thank you soooo
> much~~
> Strangely enough, the same patch quoted in your link is still relevant and
> required after 2.5 years and 4 major release!
> Roger, do you meant to submit your patch but some how get it lost?

I guess I completely forgot about it and never properly sent it to the list,
sorry. The problem is that now I don't have a system that would allow me to
test it, so if I need to resend it I would need some confirmation that it's
still working as expected. From code inspection the issue seem to be there
still.

Yes, that patch is definitely required and working.

While through eyeballing I think the patch should be able to apply directly, the automatic patch failed and I had to do it manually. I suspect this is due to some format change to the patch in the email archive.

> Without the patch:
> frontend `/local/domain/5/device/vbd/51712' devtype `vbd' expected backend
> `/local/domain/0/backend/qdisk/5/51712' got
> `/local/domain/1/backend/vbd/5/51712', ignoring
> frontend `/local/domain/5/device/vbd/51712' devtype `vbd' expected backend
> `/local/domain/0/backend/qdisk/5/51712' got
> `/local/domain/1/backend/vbd/5/51712', ignoring
>
> With the patch:
> Using xvda for guest's hda
> ******************* BLKFRONT for /local/domain/9/device/vbd/51712 **********
>
>
> backend at /local/domain/1/backend/vbd/9/51712
> 156250000 sectors of 512 bytes
> **************************
> blk_open(/local/domain/9/device/vbd/51712) -> 5
>
> However, I do NOT have the luck as Kuba had for a working system. (My first
> attempt yesterday at least give me a booting screen :-))
> What I see is the following errors:
> Parsing config from ruibox.cfg
> libxl: error: libxl_dm.c:1963:stubdom_xswait_cb: Stubdom 9 for 8 startup:
> startup timed out
> libxl: error: libxl_create.c:1504:domcreate_devmodel_started: device model
> did not start: -9
> libxl: error: libxl_device.c:1264:device_destroy_be_watch_cb: timed out
> while waiting for /local/domain/1/backend/vbd/9/51712 to be removed
> libxl: error: libxl.c:1647:devices_destroy_cb: libxl__devices_destroy
> failed for 9
> libxl: error: libxl_device.c:1264:device_destroy_be_watch_cb: timed out
> while waiting for /local/domain/1/backend/vbd/8/51712 to be removed
> libxl: error: libxl.c:1647:devices_destroy_cb: libxl__devices_destroy
> failed for 8
> libxl: error: libxl.c:1575:libxl__destroy_domid: non-existant domain 8
> libxl: error: libxl.c:1534:domain_destroy_callback: unable to destroy guest
> with domid 8
> libxl: error: libxl.c:1463:domain_destroy_cb: destruction of domain 8 failed

I'm not really sure about what's going wrong here, did you create the driver
domain guest with "driver_domain=1" in the config file?

Yes I did, even though I do not understand what is going on behind that config. The manual is not clear enough and the tutorial even does not mention it at all.

Do you have any suggestion about what I should do next to help understanding the situation here?

G.R.

Roger.

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Re: [Xen-users] HVM domU on storage driver domain