Thin disk po alokovani datastore priestoru nema vykonnostnu degradaciu

Zaujimavy postreh: Thin disk format VMDK virtualneho disku po alokovani blokov na podkladovom VMFS datastore nema vykonnostnu degradaciu oproti Thick Zeroed, resp. Thick Eager Zeroed formatom.

Dalsia zaujima vec je nasledovne:
In VMware Infrastructure 3.5, the CLI tools (service console or RCLI) could be used to configure the virtual disk format to any type, but when created via the GUI, certain configurations were the default (with no GUI option to change the type)

* On VMFS datastores, new virtual disks defaulted to Thick (zeroedthick)
* On NFS datastores, new virtual disks defaulted to Thin
* Deploying a VM from a template defaulted to eagerzeroedthick format
* Cloning a VM defaulted to an eagerzeroedthick format

This is why the creation of a new virtual disk has always been very fast, but in VMware Infrastructure 3.x cloning a VM or deploying a VM from a template (even with virtual disks that are nearly empty) took much longer.

Zdroj:
Strana 3, cast Thin Disks vo VMware dokumente Performance Study of VMware vStorage Thin Provisioning
http://www.vmware.com/pdf/vsp_4_thinprov_perf.pdf

Thin on Thin? Where should you do Thin Provisioning – vSphere 4.0 or Array-Level?
http://virtualgeek.typepad.com/virtual_geek/2009/04/thin-on-thin-where-should-you-do-thin-provisioning-vsphere-40-or-array-level.html