I am working on a large ESXi deployment and thought I would start writing down some of the lessons learned. I will try to create a single post every week, if I can find the time that is.
There are two things that stood out the couple of days, on a technical level, when I was reading the ESXi installable documentation:
One of the things that used to be a requirement was the Scratch Partition. It appears that with vSphere this requirement has been removed:
During the autoconfiguration phase, a 4GB VFAT scratch partition is created if the partition is not present on another disk. When ESXi boots, the system tries to find a suitable partition on a local disk to create a scratch partition. The scratch partition is not required.
Of course this does not necessarily mean that you do not need one as explained in the second part of the paragraph:
It is used to store vm-support output, which you need when you create a support bundle. If the scratch partition is not present, vm-support output is stored in a ramdisk. This might be problematic in low-memory situations, but is not critical.
So the question remains what would my recommendation be? The answer is it depends, yes I know the easy way out. But when you have enough RAM on a host and from experience know that usually you only create support dumps on hosts which are in maintenance mode then don’t worry about it and don’t create it. However if you feel there is a need to create vm-support dumps while running production make sure there is a scratch partition with enough free space available.
Yes ESXi is fully supported but there are some restrictions:
- Boot from FC SAN – Experimental Support
- Stateless PXE Boot – Experimental Support
Now what does “experimental support” mean? According to the VMware website it means the following:
VMware includes certain “experimental features” in some of our product releases. These features are there for you to test and experiment with. VMware does not expect these features to be used in a production environment. However, if you do encounter any issues with an “experimental feature”, VMware is interested in any feedback you are willing to share. Please submit a support request through the normal access methods. VMware cannot, however, commit to troubleshoot, provide workarounds or provide fixes for these “experimental features”.
So does that mean that in the case of stateless the booting process is experimental? Or the installation process in the case of boot from FC SAN?
No it does not. Everything related to ESXi is “experimental”. So what does this mean? Imagine you are facing serious storage issues and you just called VMware. VMware analyzes your environment and notices that it’s a PXE booted environment, they will more than likely give your support call a lower priority. Not only a lower priority but the support is “best effort”, no guarantees.