VMware Solutions Discussions

Rapid Cloning Utility / FlexClone


We are in the process of rolling out a VDI Infrastructure and I was wondering if anyone has used the rapid cloning utility in an ISCSI/Lun environment? I have read both Netapp and VMware VDI Best Practices and the Rapid Cloning Utility overview and they both are different in their approach, so I am looking for someone with real experience in doing this. I would like to create 100 Windows XP workstations, 50 per controller, and 25 per LUN. The workstations will have a 20 GB hard drive and 512 MB of ram. Thanks for the help.




It is supported for nfs datastores only.




RCU 1.0 can be used for VMFS datastores however the cloning of the gold vmdk has to be done with RFWM and the mouting by hand.  But otherwise RCU can be used to clone the VM and apply the guest customization.

Hope this helps...



As Chris said you can use RCU 1.0 with VMFS datastore but some steps are manual or you need to script them (not hard). Same as a NFS datastore you create a "gold" VMFS data LUN. In this LUN you place as many VMs as you want per LUN. Be sure that before you do this that you have the LSI SCSI driver loaded in to the image BEFORE you clone (learned that the hard way!).  You can then clone out the VMDK file by using Virtual Center (slow) or by using the RFWM tool included in the RCU 1.0 package (fast!). In this LUN you then want to organize the VMDK files to all be in a single folder. Be sure not to have anything BUT vmdk files in that folder. Once this completes, you need to deduplicate the volume and unmap it from the ESX environment.

Next just like with NFS you make a single VM template that has no disk file as part of the template.

You are now set up. To deploy a new batch of VMs here are the steps to follow:

1. Create a FlexClone of the "gold" volume and map it to the ESX environment. Insure that your ESX environment is set to resignature the volume and mount it. You will want to rename it from "snap-xxxyyy" to something useful

2. Use the RCU 1 Command line to specify the new datastore, the folder in which the VMDKs are stored, the template to use and the customization file to use. Optionally you can choose to create fewer VMs than are in the folder but usually you would want them all.

Instructions for the command line are included in the RCU 1.0 documentation.

As you can see the creation of the FlexClone, mounting and renaming could quite easily be scripted or it is a small manual effort.

Admitedly it is much more effort than the right click you have with RCU 2.0 but still a very fast way to create a large number of VMs in a small amount of time.

The vStorage API promised in VI4 aka vSphere could open up similar functionality to VMFS datastores with a future version of RCU but it is too soon to promise that as VI4 is not yet out.




The vStorage API will not be in vSphere (v4.0), but a follow-on release.  RCU 2.0, as a vCenter plug-in, begins to highlight the power of integrated storage-management with VMware will provide.  But it's not leverging the vStorage API.


Thanks Brian! That wasn't clear before...


It was confusing, because VMware announced the vStorage API concept at VMworld US (Sept.2008) and various vendors have been showing bits and pieces of support for several months now.  But they were all demos working against VMware code that isn't officially shipping yet.