I'm debating on doing an ESXi 4.1/5.0 installation on a USB stick or a pair of 32GB SATA II SSDs (RAID1 mirror). According to VMWare's documentation, when ESXi is booting it looks for a 4GB space for a scratch partition. Assuming the USB stick I use has adequate storage (say 16GB), is there any advantage to installing ESXi on an SSD or better yet, and SSD RAID1 mirror? Note: The documentation states that ESXi takes up 5.2GB of free space on disk; 5.2GB + 4GB = 9.2GB which is well below the 16GB for the USB stick.
I'd prefer to use the SSDs for something other than the ESXi installation. I think my main concern is if the USB stick dies for whatever random reason. Can I just reinstall ESXi on another USB stick and ESXi will pickup as if nothing happened?
According to VMWare's ESXi 5.0 Performance Best Practices (PDF Link):
You can optionally configure a special host cache on an SSD (if one is installed) to be used for the new swap to host cache feature. This swap cache will be shared by all the virtual machines running on the host, and host-level swapping of their most active pages will benefit from the low latency of SSD. This allows a relatively small amount of SSD storage to have a potentially significant performance impact
NOTE Using swap to host cache and putting the regular swap file in SSD (as described below) are two different approaches for improving host swapping performance. Swap to host cache makes the best use of potentially limited SSD space while also being optimized for the large block sizes at which some SSDs work best.