[Xen-users] Problem finding Block device statistics for a Xen domU using libvirt API.

["shashank rachamalla" <shashank.rachamalla@xxxxxxxxx>]

I am using fedora core 8 with two domUs installed on xen, CentOS and Fedora Core 6. I manually created a 100MB block disk device and attached it to centos domU using the following set of commands.

creating a block device

 dd if=/dev/zero of=/xen/dsk.img bs=1024 count=100000
 
 mke2fs -q /xen/dsk.img


attaching a block device to domain

 xm block-attach centOS file:///xen/dsk.img /dev/hdc w


I can successfully access the above device in both domU and dom0.
The following is the XML description for centos domain fetched using  virDomainGetXMLDesc("centos",0);


<domain type='xen' id='1'>
  <name>centOS</name>
  <uuid>e335a8f8-405d-33f0-5c6a-bac8282c3cb1</uuid>
  <bootloader>/usr/bin/pygrub</bootloader>
  <os>
    <type>linux</type>
  </os>
  <memory>204800</memory>
  <currentMemory>190464</currentMemory>
  <vcpu>1</vcpu>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <devices>
    <interface type='bridge'>
      <source bridge='virbr0'/>
      <target dev='vif1.0'/>
      <mac address='00:16:3e:65:56:dc'/>
      <script path='vif-bridge'/>
    </interface>
    <disk type='file' device='disk'>
      <driver name='file'/>
      <source file='/var/lib/xen/images/centos.img'/>
      <target dev='xvda'/>
    </disk>
    <disk type='file' device='disk'>
      <driver name='file'/>
      <source file='///xen/dsk.img'/>
      <target dev='/dev/hdc'/>
    </disk>
    <input type='mouse' bus='xen'/>
    <graphics type='vnc' port='5900' keymap='en-us'/>
    <console tty='/dev/pts/3'/>
  </devices>
</domain>

I am using the function virDomainBlockStats(dom,"xvda",&blstructure,sizebl) to fetch the block statistics where

   dom is virDomainPtr 
   blstructure is virDomainBlockStatsStruct 
   size_t sizebl=sizeof(blstructure);

and i can properly print read/write bytes and requests for "xvda", but if i use "/dev/hdc" in the place of "xvda" i get the following error
libvir: Linux Stats error : this function is not supported by the hypervisor: xenLinuxDomainBlockStats: unsupported path (use xvda, hda, etc.)

I tried using "hdc" but it did not work.

plz let me know if i am doing anything wrong. Thanks in advance.
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