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On Fri, Mar 11, 2016 at 2:07 PM, Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote:

On Mon, Mar 07, 2016 at 04:46:39PM -0500, Paul Mogren wrote:
> Hey all,
>
> I'm trying to get a storage domain up and running in Xen 4.4. I'm currently
> using Ubuntu 14.04 for the dom0, storage domain and guest. I'm currently
> following the steps here,
> http://wiki.xenproject.org/wiki/Storage_driver_domains, but am not having
> any luck.
>
> *I received this dmesg error on the guest during start-up:*
> xenbus_probe_frontend: Timeout connecting to device: device/vbd/51715
> (local state 3, remote state 2)
>
> This means the guest (in state 3) is initialised and waiting for a
> connection from a peer, and the storage-domain (in state 2) is finished
> with the early initialisation but is waiting for information from the peer
> or hot-plug scripts. This would imply to me that there is a communication

Right, like actually hooking up the disk (/home/storage/disk.img)?
to the guest.

Do you have anything in the storage domain to process udev? Ah wait you
have 'disable_udev'.

In which case I think you need the xl daemon to act for you?

Roger would know but he is on vacation. CC-ing him just in case.

> error between the xen-blkfront and xen-blkback drivers or an error in the
> scripts.
>
> *However, on the storage-domain I receive this dmesg:*
> [ 2987.170473] xen-blkback: event-channel 19
> [ 2987.170761] xen-blkback: /local/domain/3/device/vbd/51715:using single
> page: ring-ref 10
> [ 2987.171319] xen-blkback: ring-pages:1, event-channel 19, protocol 1
> (x86_64-abi) persistent grants

>
> Is this the information that the xen-blkback driver is waiting for? If so,
> why does it not continue through the initialisation process? If not, what
> information is the xen-blkback driver waiting for, and how do I ensure the
> front-end and back-end drivers will establish a connection?
>
> I've attached the output of xenstore-ls and the dmesg outputs of the guest
> and storage domain.
>
> Thanks in advanced,
> Paul Mogren

> tool = ""
> xenstored = ""
> local = ""
> domain = ""
> 0 = ""
> name = "Domain-0"
> domid = "0"
> memory = ""
> target = "6833564"
> static-max = "4294967292"
> freemem-slack = "247980"
> device-model = ""
> 0 = ""
> state = "running"
> libxl = ""
> disable_udev = "1"
.. snip..
> 2 = ""
> vm = "/vm/081ff22d-7f4b-4c46-a6b1-4deed1edc1c2"
> name = "storage-domain"
> cpu = ""
> 0 = ""
> availability = "online"
> 1 = ""
> availability = "online"
> memory = ""
> static-max = "524288"
> target = "524289"
> videoram = "-1"
> device = ""
> suspend = ""
> event-channel = ""
> vbd = ""
..
> backend = ""
> vbd = ""
> 3 = ""
> 51715 = ""
> frontend = "/local/domain/3/device/vbd/51715"
> params = "/home/storage/disk.img"

> script = "/etc/xen/scripts/block"
> frontend-id = "3"
> _online_ = "1"
> removable = "0"
> bootable = "1"
> state = "2"
> dev = "xvda3"
> type = "phy"
> mode = "w"
> device-type = "disk"
> max-ring-page-order = "4"

> 3 = ""
> vm = "/vm/23918c38-5db7-458d-a151-22726de62710"
> name = "guest"
> cpu = ""
> 0 = ""
> availability = "online"
> 1 = ""
> availability = "online"
> memory = ""
> static-max = "524288"
> target = "524289"
> videoram = "-1"
> device = ""
> suspend = ""
> event-channel = ""
> vbd = ""
.. snip..
> 51715 = ""
> backend = "/local/domain/2/backend/vbd/3/51715"
> backend-id = "2"
> state = "3"
> virtual-device = "51715"
> device-type = "disk"
> protocol = "x86_64-abi"
> ring-ref = "10"
> event-channel = "19"
> feature-persistent = "1"

Thanks Konrad for the reply.

I actually got it working though. The problem was the image that I was using (which I made with 'dd if=/dev/zero of=/home/storage/disk.img bs=1M count=10') had to be mounted as a loop back device. So I just ran 'losetup /dev/loop0 /home/storage/disk.img' and changed the configuration file for the guest to look for the target /dev/loop0.

Re: [Xen-users] [Xen-devel] Storage Domain in Xen 4.4