Insufficient disk space on datastore error

[Rohail2004]

I just created a new VM and the datastore has 1GB free, but when I try to power on the VM I am getting the error "Insufficient disk space on datastore error".

What is the minimum data space require to power on the VM? I thought 1GB is plenty of space..

[weinstein5]

The amount of space needed on the datastore depnds on the memory assigned to the vm because on power on a per vm vmkernel swap file is created and its size is equal to the amount of memory assigned to vm minus its reservation - so if you assigned 2 GB to you VM and do not have a reservation than your need 2 GB for the swap file -

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[Rohail2004]

Ya i got it now, but I have a question... I have to upgrade memory on some VM's from 1GB to 2GB, the capacity of the datastore is 400GB, but only 72MB is free.. at this time the VM has 1GB, so I can't upgrade to 2GB memory correct?

[weinstein5 · Accepted solution]

That is correct as long as you do not have a reservation defined because remember the size of the per vm vmkernel swap file is equal to the memory assigned to the vm minus the memory reservation -

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