Citrix Systems 6 manual Converting Between VDI Formats, Probing an SR

To check if an SR has been upgraded, verify that its sm-config:use_vhdkey is true. To check if a VDI was created with type=raw, check its sm-configmap. The sr-param-listand vdi-param-listxe commands can be used respectively for this purpose.

Creating a Raw Virtual Disk Using the xe CLI

1.Run the following command to create a VDI given the UUID of the SR you want to place the virtual disk in:

xe vdi-create sr-uuid=<sr-uuid>type=user virtual-size=<virtual-size>\ name-label=<VDI name> sm-config:type=raw

2.Attach the new virtual disk to a VM and use your normal disk tools within the VM to partition and format, or otherwise make use of the new disk. You can use the vbd-createcommand to create a new VBD to map the virtual disk into your VM.

Converting Between VDI Formats

It is not possible to do a direct conversion between the raw and VHD formats. Instead, you can create a new VDI (either raw, as described above, or VHD if the SR has been upgraded or was created on XenServer 5.5 or later) and then copy data into it from an existing volume. Citrix recommends that you use the xe CLI to ensure that the new VDI has a virtual size at least as big as the VDI you are copying from (by checking its virtual-size field, for example by using the vdi-param-listcommand). You can then attach this new VDI to a VM and use your preferred tool within the VM (standard disk management tools in Windows, or the dd command in Linux) to do a direct block-copy of the data. If the new volume is a VHD volume, it is important to use a tool that can avoid writing empty sectors to the disk so that space is used optimally in the underlying storage repository — in this case a file-based copy approach may be more suitable.

Probing an SR

The sr-probecommand can be used in two ways:

1.To identify unknown parameters for use in creating a SR.

2.To return a list of existing SRs.

In both cases sr-probeworks by specifying an SR type and one or more device-configparameters for that SR type. When an incomplete set of parameters is supplied the sr-probecommand returns an error message indicating parameters are missing and the possible options for the missing parameters. When a complete set of parameters is supplied a list of existing SRs is returned. All sr-probeoutput is returned as XML.

For example, a known iSCSI target can be probed by specifying its name or IP address, and the set of IQNs available on the target will be returned:

xe sr-probe type=lvmoiscsi device-config:target=<192.168.1.10>

Error code: SR_BACKEND_FAILURE_96

Error parameters: , The request is missing or has an incorrect target IQN parameter, \ <?xml version="1.0" ?>

<iscsi-target-iqns> <TGT>

<Index>

0

</Index>

<IPAddress>

192.168.1.10

</IPAddress>

<TargetIQN>

iqn.192.168.1.10:filer1

</TargetIQN>

</TGT> </iscsi-target-iqns>

Probing the same target again and specifying both the name/IP address and desired IQN returns the set of SCSIids (LUNs) available on the target/IQN.

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