Questions[kpartx](server)

I have a VM running under kvm (it is a .img file), the server it runs on crashed hard and restarted and finally got things up... I think I goofed and ran

yum install -y qemu-kvm

Which I am sure updated a ton of stuff on a very old unpdated os. I had issues after this machine died having it see vms were there like the KVM itself (the image files were there but they were not 'registered' anywhere). Not sure how I got that back but all the VMS did virsh start but one...it gives an error:

[root@sdss4-server1 ~]# virsh start sdss-host2
setlocale: No such file or directory
error: Failed to start domain sdss-host2
error: unsupported configuration: Only a single IDE controller is supported for this machine type

Did my file get corrupted? Can I repair it? I would LOVE to get this VM running again as there was no backup and some of the data needs to get off it. (I thought I could mount .img files in linux somehow? but I tried the following)

kpartx -av sdsshost2.img
add map loop0p1 (253:2): 0 208782 linear /dev/loop0 63
add map loop0p2 (253:3): 0 10490445 linear /dev/loop0 208845
device-mapper: resume ioctl on loop0p3  failed: Invalid argument
create/reload failed on loop0p3
add map loop0p3 (0:0): 0 62916711 linear /dev/loop0 10699290


[root@sdss4-server1 vm-cache]# sudo mount /dev/mapper/loop0p2 /mnt/host2
mount: unknown filesystem type 'swap'

[root@sdss4-server1 vm-cache]# sudo mount /dev/mapper/loop0p1 /mnt/host2

(I think this is a boot and the files in it are:)


System.map                      initrd-2.4.21-27.0.2.EL.img             vmlinux-2.4.21-27.0.2.ELsmp
System.map-2.4.21-27.0.2.EL     initrd-2.4.21-27.0.2.ELsmp.img          vmlinux-2.4.21-32.0.1.EL
System.map-2.4.21-27.0.2.ELsmp  initrd-2.4.21-32.0.1.EL.img             vmlinux-2.4.21-32.0.1.ELsmp
System.map-2.4.21-32.0.1.EL     initrd-2.4.21-32.0.1.ELsmp.3w-9xxx.img  vmlinuz-2.4.21-27.0.2.EL
System.map-2.4.21-32.0.1.ELsmp  initrd-2.4.21-32.0.1.ELsmp.img          vmlinuz-2.4.21-27.0.2.ELsmp
config-2.4.21-27.0.2.EL         initrd-2.4.21-52.ELBOOT.img             vmlinuz-2.4.21-32.0.1.EL
config-2.4.21-27.0.2.ELsmp      kernel.h                                vmlinuz-2.4.21-32.0.1.ELsmp
config-2.4.21-32.0.1.EL         message                                 vmlinuz-2.4.21-52.ELBOOT
config-2.4.21-32.0.1.ELsmp      message.ja
grub                            vmlinux-2.4.21-27.0.2.EL

Certainly not what I was looking for, it appears the loop0p3 is what I want to mount but the kpartx gives an error on that I do not understand fully.

So is my virtual drive/disk bad? Anything I can do to recover this some how?

The hosts definition file:

<domain type='kvm'>
  <name>sdss-host2</name>
  <uuid>36637cc5-63a1-4485-9a41-31afafb352dd</uuid>
  <memory unit='KiB'>4194304</memory>
  <currentMemory unit='KiB'>4194304</currentMemory>
  <memoryBacking>
    <hugepages/>
  </memoryBacking>
  <vcpu placement='static' cpuset='21'>1</vcpu>
  <cputune>
    <emulatorpin cpuset='21'/>
  </cputune>
  <os>
    <type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type>
    <boot dev='hd'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <pae/>
  </features>
  <cpu mode='custom' match='exact' check='partial'>
    <model fallback='allow'>coreduo</model>
    <vendor>Intel</vendor>
  </cpu>
  <clock offset='utc'/>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <emulator>/usr/libexec/qemu-kvm</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='none'/>
      <source file='/vm-cache/sdsshost2.img'/>
      <target dev='hda' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>
    <disk type='block' device='disk'>
      <driver name='qemu' type='raw' cache='none' io='native'/>
      <source dev='/dev/sdi'/>
      <target dev='hdb' bus='ide'/>
      <address type='drive' controller='0' bus='0' target='0' unit='1'/>
    </disk>
    <controller type='usb' index='0' model='piix3-uhci'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <controller type='ide' index='1'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/>
    </controller>
    <interface type='direct'>
      <mac address='52:54:00:2d:d1:ee'/>
      <source dev='enp4s0f0' mode='vepa'/>
      <model type='rtl8139'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
    <serial type='pty'>
      <target type='isa-serial' port='0'>
        <model name='isa-serial'/>
      </target>
    </serial>
    <console type='pty'>
      <target type='serial' port='0'/>
    </console>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <graphics type='vnc' port='-1' autoport='yes' listen='127.0.0.1' keymap='en-us'>
      <listen type='address' address='127.0.0.1'/>
    </graphics>
    <video>
      <model type='vga' vram='16384' heads='1' primary='yes'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </memballoon>
  </devices>
</domain>

I am trying to learn how to use kpartx, and am having some trouble. My end goal is to use nested LVMs for virtual machines, where the VM's "/home" is in one nested LVM and the rest of the VM is on a second nested LVM, so I can use snapshots for /home and /"everythingelse".

When I issue "kpartx -av /dev/vg2/LVM1", I get no output including no output telling me the name of the new nested LVM. Likewise, no output from "kpartx -l /dev/vg2/LVM1". So without the new nested volume names, I can't mount or create a file system. My best guess is the nested LVMs are not actually being created....

Q: Is there something missing in my Kpartx install (apt-get install kpartx seemed to install as expected)? Does Kpart not work on RAID1 or have problems with Wheezy?

Some description off my environment:

-Encrypted RAID1, LVM, Two volume groups (I'm trying to use Kpartx on vg2), Wheezy; Linux Vserver (VM environment)

Thanks!

I want to create a backup of a LVM volume (Xen DomU's), however a LVM volume can have multiple partitions and those are dynamic (I cannot guarantee LVM #1 has 1 partition and LVM #2 has 3 etcetera).

I'm using kpartx to mount a LVM volume, however it will create multiple mappings (1 for each partition + 1 swap) and I want to use rdiff-backup to backup the volume. But as I don't know how many partitions a volume has I cannot rely on this.

Now my question is: is there any way to let kpartx map all partitions but within the same "file"? For examply only /dev/mapper/lvm1 instead of /dev/mapper/lvm1, /dev/mapper/lvm2, /dev/mapper/lvm3 /dev/mapper/lvm5 (1 to 3 are partitions and 5 is swap).

I need this to use rdiff-backup to backup and restore a complete LVM volume

I am mounting a KVM disk (LVM) following these commands :

# losetup /dev/loop0 foo.img
# kpartx -av /dev/loop0
# mount /dev/mapper/loop0p1 /mnt

# unmount /mnt
# kpartx -dv /dev/loop0
# losetup -d /dev/loop0

Problem is when I want to do kpartx -d /dev/loop0 I get :

    device-mapper: remove ioctl failed: Device or resource busy
    device-mapper: remove ioctl failed: Device or resource busy

I tried looking for it with lsof, but I can't find anything, anyone any idea how I can force this or what I am doing wrong?