
In the VMware ESXi 6.x partitions layout, usually, there is a partition called “scratch” that hosts the log, the updates, and other temporal files. Scratch space is configured automatically during installation or first boot of an ESXi host and is not required to be manually configured.
If you install ESXi on a local hardware disk (or also if you are using a remote LUN in “boot from SAN” mode), this partition is built during the installation phase (it’s 4 GB Fat16 partition created on the target device during installation, if there is sufficient space). If you install ESXi on a USB connected mass storage (like the SD cards), then this partition is usually skipped and the ramdisk will be used instead.