Class 8 VMware Storage Basics Part 01

In VMware virtualization, storage refers to the way virtual machines (VMs) access and store their data, which is crucial for their operation and persistence. VMs use virtual disks, which are stored as files on datastores, allowing them to access storage as if they were local devices. VMware supports various storage models, including traditional SAN, NFS, and Fiber Channel, as well as software-defined storage (SDS) models like vSAN. Here's a more detailed breakdown: 1. Virtual Disks and Datastores: Virtual Disks: These are files that contain the operating system, applications, and other data for a VM. They are stored on datastores. Datastores: These are logical containers that hide the details of the physical storage device and provide a uniform way for ESXi hosts to store virtual machine files. VMDK: Virtual disks are typically stored as VMDK files on a datastore. 2. Storage Models: Traditional Storage Models: SAN (Storage Area Network): A network of storage devices that can be accessed by multiple servers, allowing VMs to access storage as if it were a local disk. NFS (Network File System): A file system on a NAS (Network Attached Storage) device, where ESXi hosts can mount NFS shares as datastores. Fiber Channel (FC): A high-speed network protocol used to connect storage devices to servers, often used in enterprise environments. Software-Defined Storage (SDS): vSAN (Virtual SAN): A software-defined storage solution that pools local and direct-attached storage devices across a vSphere cluster, creating a shared datastore. 3. Key Concepts: VMFS (Virtual Machine File System): A high-performance file system optimized for storing virtual machines, commonly used on SAN and NAS storage. Thin Provisioning: A storage optimization where a VMDK starts small and grows as data is written, allowing for efficient use of storage space. Storage Policy Based Management (SPBM): A feature that allows users to define performance, availability, and redundancy requirements for storage, ensuring compliance with business needs. 4. How Virtual Machines Access Storage: When a VM accesses its virtual disk, it sends SCSI commands to the datastore. The ESXi host then translates these commands into the appropriate protocol (e.g., FC, iSCSI, NFS) to communicate with the physical storage device.