Hyper-V Storage Technology (1)

1. Hyper-V virtual hard disk format:

The virtual hard disk provides storage space for virtual machines. in virtual machines, the virtual hard disk function is equivalent to a physical hard disk, which is used as a physical hard disk by virtual machines. Microsoft provides two virtual hard disk formats: VHD and VHDX. Before WindowsServer2012, Hyper-V virtual hard disk format was mainly in. VHD format, which broke the limit of 2 TB and supported a maximum of 64 TB. It is also a recommended virtual hard disk format by Microsoft. The main functions of VHDX format are as follows:

1): the storage capacity of the supported virtual hard disks is up to 16 TB;

2): by recording the updates to the VHDX metadata structure, data can be protected from being damaged when the power supply fails;

3): The alignment mode of the virtual hard disk format is improved, which can work better on large sector disks;

4): Dynamic disks and large data block sizes of different disks can meet workload requirements;

5): A 4 kb logical sector Virtual Disk can provide high performance when applications and workloads designed for 4 kb sectors use the disk;

6): it is sufficient to store custom metadata about the files that users may want to record, such as OS versions or patches for applications;

7): efficiently indicates that the data is also called "cropping"), so that the file size is smaller and the basic physical storage device is allowed to recycle unused space. Tailoring physical disks that need to be directly connected to virtual machines or SCSI disks and hardware compatible with tailoring .)

Ii. virtual hard disk type:

WindowsServer2012 provides four types of virtual hard disks: "fixed size", "dynamic expansion", "differential disk", and direct-to-hard disk.

Fixed size: This type of disk provides better performance. We recommend that you use it to run servers with applications with advanced disk activity. The size of the created virtual hard disk file is the size of the virtual hard disk and will not be changed when data is deleted or added.

Dynamic Scaling: This type of disk makes better use of the physical storage space. We recommend that you use it for servers that do not include applications with intensive disk usage. The virtual hard disk is small at the time of initial creation, but will gradually become larger as data is added to it.

Differential Disk: This type of disk has a parent-child relationship with another disk to be maintained. You can change the data or operating system without affecting the parent disk, so that you can easily restore the changes, all the sub-disks must have the same virtual hard disk format as the parent disk VHD or VHDX ).

Iii. Supported hard disk types:

Virtual machines deployed by Hyper-V Support the Storage types of mainstream vendors on the market, including DAS, NAS, FCSAN, and IscsiSAN. The device types include IDE devices and SCSI devices:

1) IDE device: Hyper-V uses a simulated device with an IDE controller. You can have up to two IDE controllers, and each controller can have two disks.

2) SCSI device: each virtual machine can support up to 256 SCSI devices, 4 SCSI controllers, and each controller can support up to 64 disks ). The SCSI controller uses a device designed for virtual machines and uses virtual machine bus for communication.

The steps for creating a virtual hard disk are as follows:

Step 1: Open the Hyper-V Management window, and select create virtual hard disk in the right pane.

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Step 2: select the virtual hard disk type:

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Step 3: configure a virtual hard disk:

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Step 4: create a virtual hard disk

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4. manage Virtual Disks

The virtual hard disk function is equivalent to a physical hard disk. Therefore, the administrator can expand the virtual hard disk and reduce the disk space occupied by the virtual hard disk, so that the number of virtual hard disks can be adjusted easily for the virtual machine.

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Expansion: A large virtual hard disk is planned when a virtual hard disk is first deployed. However, as the data storage volume increases, we need to expand the virtual hard disk to store more data. In Windows, you can use the hard disk management tool or the Diskpart command line to expand the volume, or create a new volume by attaching a new virtual hard disk file. Note the following:

1) the virtual machine where the virtual hard disk is located must be closed;

2) If you create a snapshot and expand the virtual disk, all the original snapshots will become invalid. If the failure of the snapshot affects the use of the virtual machine, we recommend that you add a new virtual hard disk to the virtual machine to obtain the storage space, instead of adding the disk space on the original virtual hard disk;
3) resizing a virtual hard disk will not lose data in the original virtual hard disk, so you can use it with confidence.

Compression: reclaim unused space on a virtual hard disk. This function is used to dynamically expand a virtual hard disk. This function is most useful when a large amount of data is deleted from the virtual hard disk.

Merge: merge two disks from the sub-disk and the parent hard disk of Iceland into one virtual disk. However, we generally recommend that: if the current disk allows, we recommend that you first merge the disk into a new virtual disk and then attach the new virtual disk to the virtual machine.

Conversion: Hyper-V provides conversion between "fixed size" and "dynamic expansion" virtual hard disk types, because a large amount of IO is generated during the conversion process, therefore, it is best to select conversion when the host is not busy.

The next section describes the Hyper-V Storage Technology SMB3.0.

This article is from the Eric1990 blog, please be sure to keep this source http://eric1990.blog.51cto.com/2298455/1296786