topic VSphere 4 - Extend Datastore in vSphere™ Storage Discussions

VSphere 4 - Extend Datastore

JLinxe — Wed, 05 May 2010 09:43:00 GMT

Hi everybody,

I used to work with AIX and Virtualization solution (VIO). We used to extend the FS with adding new LUN to it.

With VMWare it is called "increase Datastore with extent". Is someone uses it in production environnement?

And after, what about the dynamic disk with windows systems? It is supported the dynamic disk in the microsoft virtual machine ?

Thank you for your help

Jerome

Re: VSphere 4 - Extend Datastore

Samcer — Wed, 05 May 2010 12:41:07 GMT

Hi JLinxe,

when speaking about Datastores we mean VMFS. In this case you can span your VMFS to a new LUN OR increase the size of the VMFS after increasing the LUN space (till 2TB). This scenario does not involve VMs virtual disk. See ESX Configuration Guidepage 104 Increase VMFS Datastores

On the other hand you may increase the VMDK (virtual disk) space and inside the guest OS use the right tool to enlarge your partition. I have no problem with Dynamic MS Windows volumes used as Data (say no OS).

my 2 cents

Sam

Re: VSphere 4 - Extend Datastore

JLinxe — Wed, 05 May 2010 13:37:43 GMT

Hi Sam,

Thank you for your answer. Did you use this kind of extend in production systems? Did you notice or know some performance gap with an extension of VMFS?

Thanks you for your help

Re: VSphere 4 - Extend Datastore

Samcer — Wed, 05 May 2010 14:26:59 GMT

just some times in few cases, successfully.

There is a bunch of consideration about this topic.

For example increasing the datastores size (Volume Grow or Span) does not mean you can create bigger VMDKs as when you created the VMFS you set the block size which will not change.

When using the SPAN option (VMFS + LUN) you may have more bandwidth as you're using multiple LUNs but you may have chosen a BAD LUN. The wizard shows you the LUN ID while: disk type, RAID type, RPM etc, etc, are missing. Furthermore SPAN is a "one-way" procedure.

Al last you may prefer to use storage vMotion to a different/bigger LUN.

Sam

Re: VSphere 4 - Extend Datastore

JLinxe — Wed, 05 May 2010 16:32:29 GMT

Hi Sam,

Thank you for your help. Now I shall test. Everybody said do not extend datastore (VMFS). Nice to heard another sound.

Bye

Jerome