Re: [Xen-devel] Xen Dom U kernel

[listmail <listmail@xxxxxxxxxxxx>]

I am relatively new to lvm and xen in general that's why I posed my 
response as questions :)
If what I have suggested *is* your issue then perhaps you should ensure 
that you already have lvm2 installed on dom0, and assuming the 
appropriate initramfs lvm hooks were created upon installation, then 
rebuild the initrd with update-initramfs -c -k <verson> so that the 
initrd you are using (from dom0) has the capability to handle lvm.
Beyond that, I really do not know whether using ramdisk = 
"/boot/initrd-2.6.32.10.img break=premount" in your pvm config would be 
a viable way to pass the parameter to initrd or not.
kishore kumar wrote:
>  
> Could you please let me know where this break=premount option should 
> be added?
> What is the location of the xen block devices. I want to load this 
> module and check giving the above option and see if it works for me. 
> Thank You.
>  
> On Mon, Apr 19, 2010 at 2:29 PM, listmail <listmail@xxxxxxxxxxxx 
> <mailto:listmail@xxxxxxxxxxxx>> wrote:
>     I don't have any issues using my dom0 kernel & initrd to boot pv
>     domU,  config has CONFIG_XEN_BLKDEV_FRONTEND=m as well.
>
>     However, thats when passing through file based images & LVM from
>     the dom0 to the domU.  Is this more of an issue when LVM is
>     implemented on the domU itself???  That's what I am seeing here.
>      Should he be adding a break=premount option to initrd and
>     checking visibility of the LVM root from busybox?
>
>
>     Pasi Kärkkäinen wrote:
>
>         On Mon, Apr 19, 2010 at 12:08:35PM -0700, kishore kumar wrote:
>          
>
>               I included
>               kernel = "/boot/vmlinuz-2.6.32.10"
>               ramdisk = "/boot/initrd-2.6.32.10.img" (This is the same
>             as my Dom 0.  As
>               I am trying to boot the same Dom 0 as my Dom U without
>             any changes)
>
>                
>
>         You cannot use the dom0 initrd/ramdisk for domU!
>
>         dom0 initrd contains drivers for the physical hardware, while
>         in the domU initrd
>         you need to have drivers for the _virtual_ hardware!
>
>         In the log below root was not found because the drivers for
>         the xen block devices
>         are not loaded.
>
>         -- Pasi
>
>
>          
>
>               disk = ['phy:sda2,sda2,w']
>               root= "/dev/VolGroup01/LogVol00 ro"
>
>                 I see my .config and I have
>               CONFIG_XEN_BLKDEV_FRONTEND=m
>               CONFIG_XEN_BLKDEV_BACKEND=y
>               CONFIG_XEN_BACKEND=y
>
>               Below is the output pasted.  Any help please on what is
>             going wrong here?
>
>               XENBUS: Device with no driver: device/vbd/2050
>
>               XENBUS: Device with no driver: device/vif/0
>
>               XENBUS: Device with no driver: device/console/0
>
>               Magic number: 1:252:3141
>
>               drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
>
>               Initalizing network drop monitor service
>
>               Freeing unused kernel memory: 3392k freed
>
>               Write protecting the kernel read-only data: 6912k
>
>               Red Hat nash version 5.1.19.6 starting
>
>               Mounting proc filesystem
>
>               Mounting sysfs filesystem
>
>               Creating /dev
>
>               Creating initial device nodes
>
>               Setting up hotplug.
>
>               Creating block device nodes.
>
>               Loading ehci-hcd.ko module
>
>               ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
>
>               insmod used greatest stack depth: 5712 bytes left
>
>               Loading ssb.ko module
>
>               Loading ohci-hcd.ko module
>
>               ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
>
>               Loading uhci-hcd.ko module
>
>               uhci_hcd: USB Universal Host Controller Interface driver
>
>               Scanning and configuring dmraid supported devices
>
>               Scanning logical volumes
>
>               Reading all physical volumes. This may take a while...
>
>               lvm used greatest stack depth: 5328 bytes left
>
>               Activating logical volumes
>
>               Volume group "VolGroup01" not found
>
>               Trying to resume from /dev/VolGroup01/LogVol01
>
>               Unable to access resume device (/dev/VolGroup01/LogVol01)
>
>               Creating root device.
>
>               Mounting root filesystem.
>
>               mount: could not find filesystem '/dev/root'
>
>               Setting up other filesystems.
>
>               Setting up new root fs
>
>               setuproot: moving /dev failed: No such file or directory
>
>               no fstab.sys, mounting internal defaults
>
>               setuproot: error mounting /proc: No such file or directory
>
>               setuproot: error mounting /sys: No such file or directory
>
>               Switching to new root and running init.
>
>               unmounting old /dev
>
>               unmounting old /proc
>
>               unmounting old /sys
>
>               switchroot: mount failed: No such file or directory
>
>               init used greatest stack depth: 4888 bytes left
>
>               Kernel panic - not syncing: Attempted to kill init!
>
>               Pid: 1, comm: init Not tainted 2.6.32.10 #2
>
>               Call Trace:
>
>               [<ffffffff8105b747>] panic+0xa5/0x167
>
>               [<ffffffff8100ed81>] ? xen_force_evtchn_callback+0xd/0xf
>
>               [<ffffffff81475d48>] ? _write_unlock_irq+0x30/0x3c
>
>               [<ffffffff8108c9f4>] ? trace_hardirqs_on_caller+0x110/0x134
>
>               [<ffffffff8108ca25>] ? trace_hardirqs_on+0xd/0xf
>
>               [<ffffffff81475d4f>] ? _write_unlock_irq+0x37/0x3c
>
>               [<ffffffff8105efa7>] do_exit+0x7e/0x701
>
>               [<ffffffff8105f6c6>] sys_exit_group+0x0/0x1b
>
>               [<ffffffff8105f6dd>] sys_exit_group+0x17/0x1b
>
>               [<ffffffff81012d72>] system_call_fastpath+0x16/0x1b
>
>               On Sat, Apr 17, 2010 at 5:22 AM, Pasi Kärkkäinen
>             <[1]pasik@xxxxxx <mailto:pasik@xxxxxx>> wrote:
>
>                 On Fri, Apr 16, 2010 at 03:24:53PM -0700, kishore
>             kumar wrote:
>                 >    I am using my Dom 0 kernel to boot as my Dom U.
>                 >    I edited /etc/xen/xmexample1 file and modified
>             only below lines
>                 >
>                 >    kernel="/boot/vmlinux-2.6.32.10"
>                 >    memory=512
>                 >    vcpus=5
>                 >    root = "/dev/VolGroup01/LogVol00 ro"
>                 >    Below is the output I pasted after freezing.  Not
>             sure what is
>                 wrong.  Can
>                 >    you please help me here??
>                 >    I doubt if I have provided the correct root option?
>                 >
>
>                 I bet that kernel has xen block frontend driver as a
>             module?
>
>                 You don't seem to have ramdisk/initrd image,
>                 so you simply don't have the driver loaded at all
>                 to access the root disk in the guest.
>
>                 You must create an initrd image that loads the driver
>             module in the
>                 guest.
>                 >
>                 >    VFS: Cannot open root device "VolGroup01/LogVol00" or
>                 unknown-block(0,0)
>                 >
>                 >    Please append a correct "root=" boot option; here
>             are the available
>                 >    partitions:
>                 >
>                 >    Kernel panic - not syncing: VFS: Unable to mount
>             root fs on
>                 >    unknown-block(0,0)
>                 >
>
>                 Root was not found - this is usually because you don't
>             have the xen
>                 blockdev frontend driver loaded.
>                 -- Pasi
>
>             References
>
>               Visible links
>               1. mailto:pasik@xxxxxx <mailto:pasik@xxxxxx>
>                
>
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