Vembu Best Practices Guide

Hyper-V Terminologies

This section comprises of terminologies you must know before configuring a backup job.  A backup plan includes the backup schedule and the other backup methods which are explained in this section

Microsoft Hyper-V

Microsoft Hyper-V is a server hypervisor that enables consolidation of a single physical server into many virtual servers (Guest VMs), all sharing the hardware resources of the host server.

Important files in a VM

A VM will consist of several files that are required for its functionality. These files will be stored in the virtual machines directory. 

• Virtual hard disk (.vhd, .vhdx , .vhds)
• Virtual machine configuration files (.xml, .vmcx, .vmrs, .vmgs)

Virtual Hard Disks Format(VHD & VHDX)

Guest VMs will be created using Virtual Hard Disk, Virtual Hard Disk is a file format which represents a virtual hard disk drive (HDD). It contains the features as same as what we find on a physical HDD, such as disk partitions and file system, etc.

VHD (Virtual hard disk)

VHDX

Virtual hard disks in .vhdx format have the following benefits: 

• VHDX can range up to 64 TB in size
• VHDX as larger block size for dynamic and differential disks
• It Provides 4-KB logical sector virtual disks
• It as  an internal log that reduces the chance of corruption
• Microsoft Hyper-V provides an option to convert disk formats from VHD to VHDX and vice versa.

SMB(Server Message Block)

SMB(Server Message Block) protocol is a network file sharing protocol allowing applications to read and write to files and requesting services from a file server. 

So far we have discussed about the VM’s virtual hard disks which are stored in the host machine. Now, a Windows Server 2012 Hyper-V host can use an SMB 3.0 file shares as shared storage for storing virtual machine (VM) configuration files, VHDs, and Checkpoints.

Cluster Shared Volumes

Cluster Shared Volumes (CSVs) are a high-availability storage technology that allows multiple cluster nodes in a cluster to have read-write access to the same LUN

Vembu Integration service - VIS

VembuIntegrationService is a proxy agent that is installed in the Hyper-V hosts when you add the Hyper-V host through Vembu BDR server. With the help of VIS agent installed in Hyper-V host servers, Disk read and CBT tracking will be performed during the backup process.

CBT Changed block tracking

CBT (Changed block tracking) is a driver which is bundled with VIS, this will be installed during the first backup in the respective Hyper-V hosts. It captures the changed blocks and saves it in the .DAT file, which will be used in the forthcoming incremental backup schedules.