Strange behavior yesterday a newly installed ESXi 4.1 machine: The vmfs3 partition used only around 27% of the disk capabilities. Meaning: From the logical harddisk of 2.86 TB only 744GB were used for VMFS.

After some extended research and several tests, it looks like the ESXi 4.1 installer may have a bug in the partitioner, causing to add a primary partition for vmfs which is smaller than it could be. But with manual tweaks on the ESXi machine and (if necessary) in a partition tool like GParted, one can get rid of this bug by manually recreating the vmfs partitions. 

I wrote a How To called VMware ESXi 4.1 does not use whole disk capacities for VMFS3 which describes in details how to manually repartition and reformat the vmfs volumes on an ESXi 4.1 machine.

Update 29.07.2010:
Meanwhile I've contacted VMware to get some information from the 'source' why ESXi is doing this. The official response is that this is a 'wanted limitation' of ESXi and it is unlikely that this limitation will disappear in the near future. So if you want to use ESXi 4.1 with a lot of disk capacity you either may have to switch to ESX (for manual partitioning) or you follow my HowTo which serves as a workaround here.