Those of you who have a good understanding of VSAN at this stage will know that a virtual machine deployed on the VSAN datastore is deployed as a set of objects, and not a set of files, which is how a VM is deployed on traditional datastores. Those objects include the VM Home Namespace, VMDKs and of course VM Swap. VM Swap is interesting, in that it only exists when the VM is powered on, but on VSAN it has always been provisioned with 100% Object Space Reservation in the past. This has some drawbacks, since it tended to consume…
In the VSAN Troubleshooting Reference Manual, the following description of VSAN.ClomMaxComponentSizeGB is provided: By default VSAN.ClomMaxComponentSizeGB is set to 255GB. When Virtual SAN stores virtual machine objects, it creates components whose default size does not exceed 255 GB. If you use physical disks that are smaller than 255GB, then you might see errors similar to the following when you try to deploy a virtual machine: There is no more space for virtual disk XX. You might be able to continue this session by freeing disk space on the relevant volume and clicking retry.
I’m currently neck-deep preparing for the next version of Virtual SAN to launch. As I prepare for all the new features that are coming (that I hope to be able to start sharing with you shortly), I’m still surprised by the misconceptions that still exist with regards to basic Virtual SAN functionality. The purpose of this post is to clear up a few of those.