Hi,
I'm trying to understand how the "Add Extent" feature works for vSphere 5.0.
Here is what I have done:
Test scenario 1:
1. Create 20GB Thick LUN on storage array.
2. Create 20GB VMFS5 datastore out of the 20GB Thick LUN (vmfs-1) on vCenter
3. On ESXi 5.0, go to vmfs-1 directory and create two 5GB eager zeroed thick vmdks
# vmkfstools -c 5g -d eagerzeroedthick <vmdk name>
4. Add Extent a Thin LUN of 20GB (on 5GB physical device). At this point, the total size of vmfs-1 is 40GB.
5. On ESXi 5.0, go to vmfs-1 directory, create another 5GB eager zeroed thick vmdk.
On storage array, the storage space corresponding to 20GB Thin LUN reached 100% usage. In other words, the third 5GB vmdk did not use any space on the original 20GB Thick LUN.
Test scenario 2:
1. Create 20GB Thin LUN (on 15GB physical device)
2. Create 20GB VMFS5 datastore out of the 20GB Thin LUN (vmfs-2) on vCenter
3. On ESXi 5.0, go to vmfs-2 directory and create two 5GB eager zeroed thick vmdks
4 Add Extent a Thick LUN of 20GB. At this point, the total size of vmfs-2 is 40GB.
5. On ESXi 5.0, go to vmfs-2 directory, create another 6GB eager zeroed thick vmdk.
The vmfs-2 datastore ran out of space. In other words, the third 6GB vmdk did not use any space on the extent (20GB Thick LUN).
It seems that both the original datastore and added extent(s) need to be Thin LUNs in order for the "Add Extent" feature to work properly. Is that right? Thanks.