Regardless of what's been shared in the KB articles and the Documentation center: Installation guide, many of the users are just doing a blind vSphere 5.5 install on their legacy hardware'.
This prompted me to write a checklist kind of post to help people to make sure the pre-requisites are met and in their environment vSphere 5.5 will run.
1. Your hardware is compliant on the VMware Compatibility Guide.
=> Make sure the firmware is up to date and its in the vSphere 5.5 support list. (Recommended especially for HP Servers.)
2. CPU supports x64 architecture with atleast 2 cores.
=> Make sure your processor type appear on the VMware Compatibility Guide.
3. Server has one or more Gigabit or 10GB Ethernet controllers which are supported and listed in VMware Compatibility Guide.
4. Server have Storage controllers with any combination of one or more of:
- Basic SCSI controllers. Adaptec Ultra-160 or Ultra-320, LSI Logic Fusion-MPT, or most NCR/Symbios SCSI.
- RAID controllers. Dell PERC (Adaptec RAID or LSI MegaRAID), HP Smart Array RAID, or IBM (Adaptec) ServeRAID controllers
5. The storage system used is supported.
6. A boot device that is minimum 1GB in size.
Note: When booting from a local disk or SAN/iSCSI LUN, a 5.2GB disk is required to allow the creation of the VMFS volume and a 4GB scratch partition on the boot device.
Disclaimer: This is not an extensive list of requirements. But its helps you to get rid of the silly mistakes that could stop from getting the feel of vSphere 5.5.
Its always recomended to follow the steps and procedures explained in VMware vSphere Documentation : vSphere Installation and Setup Guide.
~dGeorgey