How much LUN space is used by Vsphere for internal use?

[gpapstei]

Some simple question , how much space has to be left on a vmfs Lun for Vsphere usage e.g  how much space is used by Vsphere .

[RParker]

ZERO.  vSphere does not reserve any space.. if it does it's negligble, but I have never seen any reserved files.

[mcowger]

Not quite right...

There IS a small amount of space use by VMFS itself (hence the reason you can't create a VMFS < ~50MB).

There are a number of VMFS files on the datastore, espcially the ones use for SIOC, etc.

That being said, the size of those files is so close to zero as to be ignorable (<5MB) compared to the size of msot datastores (measured in hundreds of GB).

Be aware of the 'non-internal' uses that can grow the usage of a datastore that are mentioned above (snapshots, thin privisioning, etc).

[weinstein5]

Well it depends -

• If you are using thin provisioned virtual disks you will need to maintain space to account for disk growth
  
• When placing VMs on the VMFS datastoe you will need to insure there is space available for the per VM vmkernel swap file to be created or you will not be able to start the VM - this by default is created in the directory where the VZMs configuration file is stored
  
• For trouble shooting you will to make sure there is enough space for the VMs log files - but this is typuically negligible in comparison to the size of the datastore -
  

[MartinAmaro]

I usually do 10 to 15 VMs per LUN and I allow 20% free for VMKernel, snapshots, page file and vswap.