Anatomy of I/O

All the virtual machine data is eventually stored in magnetic disks. The only difference is that some are written immediately and some at a later point in time sequentially.

Let's review specific I/O workflows that are associated with VSAN:

  • Write buffer
  • Data destage
  • Read cache

Write buffer

A guest operating system within the virtual machine performs a write operation intended to the virtual disk associated to the virtual machine. The I/O is received by the Virtual SAN module on the localhost of the virtual machine that it is currently running on. On receipt of the I/O, the VSAN knows the replicas of the virtual disk and triggers a parallel write operation to the replicas. The writes are performed first on the flash devices that frontend ...

Get Getting Started with VMware Virtual SAN now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.