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Problem creating a MCS Cluster in ESXi4 U1


I tried to create two guests to use do testing on a Microsoft Server 2003 Cluster. After following the procedures as described for "Cluster in a Box" in the "Setup for Failover Clustering and Microsoft Cluster Service" I have received the following alert in the vSphere client.

"VMware ESX cannot open the virtual disk, "/vmfs/volumes/4ac15af5-86e3e6c0-8ecd-001b21200b6e/LCP PS PS N1/LCP PS PS N1_1.vmdk" for

clustering. Please verify that the virtual disk was created using the 'thick' option. Cannot open the disk '/vmfs/volumes/4ac15af5-86e3e6c0-8ecd-001b2-

1200b6e/LCP PS PS N1/LCP PS PS N1_1.vmdk' or one of the snapshot disks it depends on. Reason: Thin/TBZ disks cannot be opened in multiwriter


The GUI reports the disk type as "Thick" in the VM propoerties.

I then created the VMDK using the vmkfstools -d thick -a lsilogic -c 1G LCP PS PS N1_1.vmdk which I have used in previous versions sucessfully. vmkfstools reported "thick" is not valid. I changed the command to: vmkfstools -d zeroedthick -a lsilogic -c 1G LCP PS PS N1_1.vmdk which created the disk.

The VM would still not start.

After deleting the disks again I then recreated them using the vmkfstools -d eagerzeroedthick -a lsilogic -c 1G LCP PS PS N1_1.vmdk

The VM now starts and no alerts for the VM startup in the vSphere GUI.


1. Did I miss a step in the procedure to cause the errors?

2. Is the procedure I used the most correct?

3. Did I do something wrong or is the documentation incomplete or unclear?

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From MSCS manual for vSPhere, page 14:

Create disk:

Enter the appropriate value in Virtual disk size. Select Support clustering

features such as Fault Tolerance to create a disk in eagerzeroedthick


Have you done this operation? Anyways, your procedure was right correcting the problem.

Marcelo Soares

VMWare Certified Professional 310/410

Technical Support Engineer

Globant Argentina

Consider awarding points for "helpful" and/or "correct" answers.

Marcelo Soares
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