ESX-OSData

In the Ultra Transcenders books

2V0-16.252V0-15.252V0-18.25

Each book explains ESX-OSData in context, with comparison tables and the common traps.

Terms in this definition

• ESX

  VMware's bare-metal hypervisor, installed on each host in a VCF fleet. Up to version 9.0 it was known as ESXi.

• VMware Tools

  Drivers and services that run inside a virtual machine's operating system to boost speed and enable clean shutdowns, heartbeats and guest operations. It should be upgraded ahead of the VM's compatibility level.

• Chat message roles

  Labels on chat messages: instructions go under system, the person's input under user, the model's previous answers under assistant, and results returned by a called tool under tool (or function).

• General-purpose v1

  The older storage account kind (Storage), which lacks access tiers, Archive and premium file shares and retires on 13 October 2026. Converting to ZRS requires first upgrading to GPv2, a one-way change.

• Volume

  Holds non-tabular files sitting in cloud storage under Unity Catalog governance, addressed as /Volumes/<catalog>/<schema>/<volume>. A volume can be external or managed, and WRITE VOLUME or READ VOLUME decide who may use it.

• USB

  Universal Serial Bus, for connecting peripherals. A BitLocker startup key can live on a USB stick, and although Storage Spaces will take USB drives, using them is not advised.

Related terms

• Core dump

  When the VMkernel of an ESX host fails, the host saves a diagnostic image of its state. Possible destinations are a dump partition (ESX-OSData unless changed), a VMFS datastore file, or a remote ESX Dump Collector reached over the network.

• ESX system storage

  Core dumps, scratch space and the VMware Tools locker are held in ESX-OSData, one of the areas (alongside System Boot and a pair of boot banks) that the ESX 9.0 installer sets aside on its boot media.

• HDD

  A storage device based on magnetic disks. ESX-OSData may be placed on a dedicated one (or on SSD or NVMe), but vSAN ESA takes only NVMe drives.

• remote boot device

  The SAN device from which ESX boots, containing ESX-OSData. ESX 9.0 keeps watch on it, and if APD or PDL persists there the host halts with a purple diagnostic screen to avoid possible corruption.

• Scratch partition

  Space on an ESX host where system logs and other temporary files gathered into support bundles are written; if it is missing, a ramdisk holds the logs instead. ESX 9.0 locates it inside ESX-OSData, or it can be redirected to remote NFS or SAN storage.

• SD card

  Flash storage for booting hosts. Under ESX 9.0 only the boot banks may live on it, since keeping ESX-OSData there, or on USB, is deprecated; with no persistent device an alarm fires and ESX-OSData sits on a RAM disk.