I have a question. I need to export a VM Thin Partionned. But the problem is that this VM is too big ... Regarding to VSPHERE client, it says that this VM is about 2TO used. But someone told me that when you have a VM set up to Thin Partition, when you’ll export it, the size will not be what you see on vsphere client , it will be a lot smaller.
Is that true ?
PS : Sorry if my English is a little bad.
Thanks.
As mentioned, the resulting size of the export will be the actual utilized space stored on disk. You can reclaim space on the VMDK and see the actual usage. The following article has the vmkfstools command to do that: https://kb.vmware.com/s/article/2004155 More information about the VMDK types: https://www.vmwareblog.org/vmware-esxi-disk-provision-work-difference-one-better/
The theory of a thin provisioned disk is that it only needs to be about a large as the utilized space within it. In other words: If the disk is almost full, you will gain very little space by turning it into a thin provisioned one. If it's mostly empty you can see enormous space savings.
Note that a thin provisioned disk will see decreased I/O performance during those times when it extends to fit more data. It grows in chunks, so it will not necessarily be slower all the time, especially not on modern SSD storage where file fragmentation is a lot less of a problem.
Except for those caveats, you are correct in that the simple way to turn an existing thick provisioned disk into a thin provisioned one is to migrate it to new storage and select thin provisioning as an option during migration.
