Differential VMDKs on VMFS (vSphere 4)

[iPhun]

I am currently investigating the conversion of ~50 phsyiscal blades, each housing two VMware GSX VMs to ESX v4. All the VMs have just slight differences (being the MySQL database), the rest of the OS and application are the same. Does anyone know if VMware supports something like differential disks on ESXvSphere 4? With this, one could save some terabytes on the expensive SAN storage.

Thanks for your comments,

iPhun.

[AntonVZhbankov]

No, ESX does not have such feature for server VMs. But you can buy SAN with build-in deduplication, like NetApp FAS2000 and above.

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MCP, MCTS, VCP, VMware vExpert '2009

http://blog.vadmin.ru

[AndreTheGiant]

The linked clone technology is available only with VMware Lab Manager or VMware View Composer (this is not yet compatible with VC4).

Or (as written by Anton before) you can use a de-duplication solution at storage level (if your storage support this feature).

Andre

[ehinkle]

You can also thin provision your disk.

[lamw]

Wrong, Linked Clones is available and supported via vSphere API, here is a vSphere SDK for Perl implementation: http://engineering.ucsb.edu/~duonglt/vmware/vGhettoLinkedClone.html

For more information there is also a VMware whitepaper on how this all works via the newly introduced functionality in vSphere: http://www.vmware.com/support/developer/vc-sdk/linked_vms_note.pdf

In the past it was true, Linked Clones was only available via Lab Manager and then View.

Here is also my hacked version of Linked Clones via Service Console/Busybox console for pre-ESX(i) 4.0:

=========================================================================

William Lam

VMware vExpert 2009

VMware ESX/ESXi scripts and resources at:

VMware Code Central - Scripts/Sample code for Developers and Administrators

VMware Developer Comuunity

Twitter: @lamw

If you find this information useful, please award points for "correct" or "helpful".

[iPhun]

Hello William,

thanks for pointing me towards the Linked Clonse technology on vSphere 4. Unfortunately it is not supported within VMware HA clusters ("You can have up to eight virtual machines in a linked virtual machine group. The virtual machines in the group cannot be part of a VMware HA cluster.") so I cannot start using it.

Regards,

iPhun.