why do I need a local VMFS?

[Erwin_Zavala]

I am installing on local drive but connected to a SAN for VM storage. why does the installation of ESX create a local VMFS datastore??

[blp848]

You really don't need it. But it is useful for extra space to place patches and upgrades. It also can be used for swap space for the virtual machines with VI 3.5.

[weinstein5 · Accepted solution]

Welcome to the forums - as the other poster pointed out you really do not need it - but it is helpful occasionally to have it - the one thing to keep in mind is that if you do place a VM on local storage and this includes placing the vm's vmkernel swap file you would not be able to vmotion that vm or have it as part of a DRS/HA cluster

[TomHowarth]

Firstly welcome to the forums.

There is no actual requirement for local storage, unless you are virtualising MSCS, where it is a requirement, that said with disk sizes are they are today a spare 100GB's of storage over your Hosts could be very useful if you found your LUNs were too small as you could move your virtual machines to local storage, while you or your SAN admin create larger LUN,s

Tom Howarth

VMware Communities User Moderator

[williamarrata]

During the installation you can move it from the default location which is usually the primary partition and move it to the extended partition so that once you have edited your partitioning the way you want, take up the rest of the drive with vmfs-3 partition. Now as everyone one else said, here you can use it as you need.

Hope that helped.

[weinstein5]

Tom - actually just learned with Update 1 - using a local VMFS is no longer required for MSCS in VI-3

[TomHowarth]

You are correct, however the original poster had not mentioned the version of ESX, so I was just covering bases.

Tom Howarth

VMware Communities User Moderator

[weinstein5]

good point - after I posted I second guessed myself thinking you might have heard something -

[Texiwill]

Hello,

I create a local VMFS for DR/BC reasons. If the SAN goes down, my local VMFS has a copy of my most important VMs. This way I can launch them and not loose functionality as the SAN is repaired.

Best regards,

Edward L. Haletky

VMware Communities User Moderator

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Author of the book 'VMWare ESX Server in the Enterprise: Planning and Securing Virtualization Servers', Copyright 2008 Pearson Education.

CIO Virtualization Blog: http://www.cio.com/blog/index/topic/168354

As well as the Virtualization Wiki at http://www.astroarch.com/wiki/index.php/Virtualization