On twitter @lamw just asked a question which triggered me to blog it cause I expect this is something more people will run into sooner or later.

Anyone know if you can change the default VMFS block size in ESX4 during interactive installation?

This is something that I also ran into personally a couple of weeks ago. If you install ESX 4.0 with the defaults a large VMFS volume is created that fills up the disk. This VMFS volume has a default block size of 1MB which means a file size limit of 256GB.

In the setup there’s currently no way of changing the block size. (If I’m wrong please leave a comment.) The only way to avoid this is to create two VMFS volumes. The first one will need to be created during the installation and will be the volume on which the Service Console VMDK resides. The second VMFS volume should be created after the installation and will be hosting the VMs. Although it does sound like an unnecessary step I personally think it is a good approach. This way the chance of filling up(snapshots) your VMFS partition which hosts you Service Console is very slim.