Hey everyone,
I've got an issue that I can't quite get an answer to...from VMware or NetApp...at least as of yet anyways. I've got an Oracle 7420 which has caused us some heartache with VMware living on it. We've decided to migrate everything to a brand new NetApp 3250 cluster. I have the VAAI Plugins loaded and have provisioned the datastores using the latest NetApp VSC. The On-Tap version is 8.1.2 P3 in 7-mode. ESXi hosts are on 5.1 U1. I have not yet upgraded vCenter to 5.1 U1 from 5.1.0B. If anyone has any ideas, I'd love to hear them! (and Thank You in advance!) 
I've got a few VMs that I've migrated over from the 7420 and I couldn't figure out exactly why I was chewing up so much more space on the NetApp than was in use on the Oracle system. I found that on some of my VMs, some of the larger 100GB-provisioined disks were converted from thin provisioned (roughly 30-60% used) to thick, eager zeroed. As such, a lot of space was eaten up that was unnecessary. During my storage vMotion task, I'd specifically say Thin Provisioned (not just same as source).
I believe that Hole Punching/UNMAP is enabled/used by the storage system - some of my VMs with multiple 100GB disks all came over as thin provisioned as expected. Some of the VMs with multiple 100GB disks came over half as thin, half as thick-ez. When I move the individual disks back to the original storage system, they return to Thin provisioned format. When I bring them back to the NetApp, it goes to thick-ez again.
I ran some commands to ensure my host has the VAAI plugin loaded and is active.
~ # esxcli storage core claimrule list --claimrule-class=Filter
Rule Class Rule Class Type Plugin Matches
---------- ----- ------- ------ ----------- --------------------------------
Filter 5001 runtime vendor VAAI_FILTER vendor=HP model=P2000 G3 FC
Filter 5001 file vendor VAAI_FILTER vendor=HP model=P2000 G3 FC
Filter 5002 runtime vendor VAAI_FILTER vendor=HP model=P2000G3 FC/iSCSI
Filter 5002 file vendor VAAI_FILTER vendor=HP model=P2000G3 FC/iSCSI
Filter 5003 runtime vendor VAAI_FILTER vendor=HP model=P2000 G3 iSCSI
Filter 5003 file vendor VAAI_FILTER vendor=HP model=P2000 G3 iSCSI
Filter 5004 runtime vendor VAAI_FILTER vendor=HP model=P2000 G3 SAS
Filter 5004 file vendor VAAI_FILTER vendor=HP model=P2000 G3 SAS
Filter 65430 runtime vendor VAAI_FILTER vendor=EMC model=SYMMETRIX
Filter 65430 file vendor VAAI_FILTER vendor=EMC model=SYMMETRIX
Filter 65431 runtime vendor VAAI_FILTER vendor=DGC model=*
Filter 65431 file vendor VAAI_FILTER vendor=DGC model=*
Filter 65432 runtime vendor VAAI_FILTER vendor=EQLOGIC model=*
Filter 65432 file vendor VAAI_FILTER vendor=EQLOGIC model=*
Filter 65433 runtime vendor VAAI_FILTER vendor=NETAPP model=*
Filter 65433 file vendor VAAI_FILTER vendor=NETAPP model=*
Filter 65434 runtime vendor VAAI_FILTER vendor=HITACHI model=*
Filter 65434 file vendor VAAI_FILTER vendor=HITACHI model=*
Filter 65435 runtime vendor VAAI_FILTER vendor=LEFTHAND model=*
Filter 65435 file vendor VAAI_FILTER vendor=LEFTHAND model=*
~ # esxcli storage core claimrule list --claimrule-class=VAAI
Rule Class Rule Class Type Plugin Matches
---------- ----- ------- ------ ---------------- --------------------------------
VAAI 5001 runtime vendor HP_VAAIP_P2000 vendor=HP model=P2000 G3 FC
VAAI 5001 file vendor HP_VAAIP_P2000 vendor=HP model=P2000 G3 FC
VAAI 5002 runtime vendor HP_VAAIP_P2000 vendor=HP model=P2000G3 FC/iSCSI
VAAI 5002 file vendor HP_VAAIP_P2000 vendor=HP model=P2000G3 FC/iSCSI
VAAI 5003 runtime vendor HP_VAAIP_P2000 vendor=HP model=P2000 G3 iSCSI
VAAI 5003 file vendor HP_VAAIP_P2000 vendor=HP model=P2000 G3 iSCSI
VAAI 5004 runtime vendor HP_VAAIP_P2000 vendor=HP model=P2000 G3 SAS
VAAI 5004 file vendor HP_VAAIP_P2000 vendor=HP model=P2000 G3 SAS
VAAI 65430 runtime vendor VMW_VAAIP_SYMM vendor=EMC model=SYMMETRIX
VAAI 65430 file vendor VMW_VAAIP_SYMM vendor=EMC model=SYMMETRIX
VAAI 65431 runtime vendor VMW_VAAIP_CX vendor=DGC model=*
VAAI 65431 file vendor VMW_VAAIP_CX vendor=DGC model=*
VAAI 65432 runtime vendor VMW_VAAIP_EQL vendor=EQLOGIC model=*
VAAI 65432 file vendor VMW_VAAIP_EQL vendor=EQLOGIC model=*
VAAI 65433 runtime vendor VMW_VAAIP_NETAPP vendor=NETAPP model=*
VAAI 65433 file vendor VMW_VAAIP_NETAPP vendor=NETAPP model=*
VAAI 65434 runtime vendor VMW_VAAIP_HDS vendor=HITACHI model=*
VAAI 65434 file vendor VMW_VAAIP_HDS vendor=HITACHI model=*
VAAI 65435 runtime vendor VMW_VAAIP_LHN vendor=LEFTHAND model=*
VAAI 65435 file vendor VMW_VAAIP_LHN vendor=LEFTHAND model=*
~ # vmkfstools -P /vmfs/volumes/storagenetapp_cluster_datastore01
NFS-1.00 file system spanning 1 partitions.
File system label (if any): storagenetapp_cluster_datastore01
Mode: public
Capacity 1099511627776 (268435456 file blocks * 4096), 192524517376 (47003056 blocks) avail
UUID: d71506fa-6ca3267f-0000-000000000000
Partitions spanned (on "notDCS"):
nfs:storagenetapp_cluster_datastore01
NAS VAAI Supported: YES
Is Native Snapshot Capable: YES