Hi ,


For attaching iSCSI  disk I have tried like this 

iscsi target side :

         1 created an iqn number
            #tgtadm --lld iscsi --op new --mode target --tid 1 -T iqn.2009-06.com.eucalyptus.cluster1:store1 

        2. added one lun to it
            #tgtadm --lld iscsi --op new --mode logicalunit --tid 1 --lun 1 -b /fs.iscsi.disk

        3.To enable the target to accept any initiators, enter:
            #tgtadm --lld iscsi --op bind --mode target --tid 1 -I ALL
        4.To view the current configuration, enter:
           #tgtadm --lld iscsi --op show --mode target
iscsi initaitor side (where libvirt and xen is running)

     1. to scan for the newly created target
            #iscsiadm -m discovery -t sendtargets -p 192.168.53.14
         2. created pool file 
             <pool type="iscsi">
                 <name>sample3</name>
                 <source>
                       <host name="192.168.53.14"/>
                      <device path="iqn.2009-06.com.eucalyptus.cluster1:store1"/>
                 </source>
                 <target>
                      <path>/dev/disk/by-path</path>
                 </target>
             </pool>
          3.#virsh pool-define sample_pool.xml 
            #virsh pool-start sample3
            then it created one link like this at /dev/disk/by-path/
             ip-192.168.53.14:3260-iscsi-iqn.2009-06.com.eucalyptus.cluster1:store1-lun-1 -> ../../sdb
          4. I have attached using virsh attach-disk
              #virsh attach-disk 1 /dev/sdb xvdb
It is attached successfully , I console in vm I have checked .

But while using with eucalyptus,It is not attching.
 
I'm using eucalyptus 3.4.2 , libvirt 1.2.3 with xen4.3.1  to attach volume to vm .

eucalyptus attaching volume is done through iscsi disk , intermediate files are created while attaching  volume in xml format as below.
File 1:
                         <?xml version="1.0" encoding="UTF-8"?>
                               <disk type="block">
                                <driver cache="none" name="phy"/>
                               <source dev="/dev/disk/by-id/scsi-1IET_00230001"/>
                               <target dev="sdf" bus="scsi"/>
                               <serial>vol-759A3CDB-dev-sdf</serial>
                              </disk>

File 2:

                             <?xml version="1.0" encoding="UTF-8"?>
                             <volume>
                             <hypervisor type="xen" capability="xen+hw" bitness="64"/>
                             <id>vol-759A3CDB</id>
                              <user>AIDOMCCNSP7YNR7IEZEUX</user>
                              <instancePath>/usr/local/eucalyptus/work/AIDOMCCNSP7YNR7IEZEUX/i-ED153F84</instancePath>
                             <os platform="linux" virtioRoot="false" virtioDisk="false" virtioNetwork="false"/>
                             <backing>
                              <root type="image"/>
                             </backing>
                             <diskPath targetDeviceType="disk" targetDeviceName="sdf" targetDeviceBus="scsi" sourceType="block" serial="vol-759A3CDB-dev-sdf">/dev/disk/by-id/scsi-1IET_00230001</diskPath>
</volume>


in libvirtd.log i'm getting

error : libxlDomainAttachDeviceDiskLive:2567 : unsupported configuration: disk bus 'scsi' cannot be hotplugged.

Can u suggest how to enable or patch to scsi hotplug from libvirt which support for xen.

Can u say the meaning of PATCH 11/12 what is 11/12 means.
eg ; [libvirt] [PATCH 11/12] Properly support SCSI drive hotplug

With Regards
Prapulla Kumar R