VMware 3V0-22.21 Dumps Questions Answers

VMware vSphere ESXi can use locally attached SSDs (Solid State Disk) and flash devices in multiple ways. Since SSDs offer much higher throughput and much lower latency than traditional magnetic hard disks the benefits are clear. While offering lower throughput and higher latency, flash devices such as USB or SATADOM can also be appropriate for some use cases. The potential drawback to using SSDs and flash device storage is that the endurance can be significantly less than traditional magnetic disks and it can vary based on the workload type as well as factors such as the drive capacity, underlying flash technology, etc.

This KB outlines the minimum SSD and flash device recommendations based on different technologies and use case scenarios.

SSD and Flash Device Use Cases

A non-exhaustive survey of various usage models in vSphere environment are listed below.

Host swap cache

This usage model has been supported since vSphere 5.1 for SATA and SCSI connected SSDs. USB and low end SATA or SCSI flash devices are not supported.

The workload is heavily influenced by the degree of host memory over commitment.

Regular datastore

A (local) SSD is used instead of a hard disk drive.

This usage model has been supported since vSphere 7.0 for SATA and SCSI connected SSDs.

There is currently no support for USB connected SSDs or for low end flash devices regardless of connection type.  

vSphere Flash Read Cache (aka Virtual Flash)

This usage model has been supported since vSphere 5.5 for SATA and SCSI connected SSDs.

There is no support for USB connected SSDs or for low end flash devices.  

vSAN

This usage model has been supported since vSphere 5.5 for SATA and SCSI SSDs. For more information, see the  vSAN Hardware Quick Reference Guide .

vSphere ESXi Boot Disk

A USB flash drive or SATADOM or local SSD can be chosen as the install image for ESXi, the vSphere hypervisor, which then boots from the flash device.

This usage model has been supported since vSphere 3.5 for USB flash devices and vSphere 4.0 for SCSI/SATA connected devices.

Installation to SATA and SCSI connected SSD, SATADOM and flash devices creates a full install image which includes a logging partition (see below) whereas installation to a USB device creates a boot disk image without a logging partition.  

vSphere ESXi Coredump device

The default size for the coredump partition is 2.5 GiB which is about 2.7 GB and the installer creates a coredump partition on the boot device device for vSphere 5.5 and above. After installation the partition can be resized if necessary using partedUtil. For more information, see the  vSphere documentation .

Any SATADOM or SATA/SCSI SSD may be configured with a coredump partition.

This usage model has been supported from vSphere 3.5 for boot USB flash devices and since vSphere 4.0 for any SATA or SCSI connected SSD that is local.

This usage model also applies to Autodeploy hosts which have no boot disk.  

vSphere ESXi Logging device

A SATADOM or local SATA/SCSI SSD is chosen as the location for the vSphere logging partition ( /scratch  partition). This partition may be but need not be on the boot disk and this applies to Autodeploy hosts which lack a boot disk.

This usage model has been supported since vSphere 7.0 for any SATA or SCSI connected SSD that is local. SATADOMs that meet the requirement set forth in Table 1 are also supported.

This usage model can be supported in a future release of vSphere for USB flash devices that meet the requirement set forth in Table 1.

SSD Endurance Criteria

The flash industry often uses Tera Bytes Written (TBW) as a benchmark for SSD endurance. TBW is the number of terabytes that can be written to the device over its useful life. Most devices have distinct TBW ratings for sequential and random IO workloads, with the latter being much lower due to Write Amplification Factor (WAF) (defined below). Other measures of endurance commonly used are DWPD (Drive Writes Per Day) and P/E (Program/Erase) cycles.

Conversion formulas are provided here:

Converting DWPD (Drive Writes Per Day) to TBW (Terabytes Written):

TBW = DWPD * Warranty (in Years) * 365 * Capacity (in GB) / 1,000 (GB per TB)  

Converting Flash P/E Cycles per Cell to TBW (Terabytes Written):

TBW = Capacity (in GB) * (P/E Cycles per Cell) / (1,000 (GB per TB) * WAF)

WAF is a measure of the induced writes caused by inherent properties of flash technology. Due to the difference between the storage block size (512 bytes), the flash cell size (typically 4KiB or 8KiB bytes) and the minimum flash erase size of many cells one write can force a number of induced writes due to copies, garbage collection, etc. For sequential workloads typical WAFs fall in the range of single digits while for random workloads WAFs can approach or even exceed 100. Table 1 contains workload characterization for the various workloads excepting the Datastore and vSphere Flash Read Cache workloads which depend on the characteristics of the Virtual Machines workloads being run and thus cannot be characterized here. A WAF from the table can be used with the above P/E to TBW formula.

Select Menu > Policies and Profiles, and under Policies and Profiles, click VM Customization Specifications.

Click the Create a new specification icon.

The New VM Guest Customization Specification wizard opens.

On the Name and target OS page, enter a name and description for the customization specification and select Windows as a target guest OS.

(Optional) Select the Generate a new security identity (SID) option and click Next.

A Windows Security ID (SID) is used in some Windows operating systems to uniquely identify systems and users. If you do not select this option, the new virtual machine has the same SID as the virtual machine or template from which it was cloned or deployed.

Duplicate SIDs do not cause problems when the computers are part of a domain and only domain user accounts are used. However, if the computers are part of a Workgroup or local user accounts are used, duplicate SIDs can compromise file access controls. For more information, see the documentation for your Microsoft Windows operating system.

On the Set Registration Information page, enter the virtual machine owner’s name and organization and click Next.

On the Computer name page, enter a computer name for the guest operating system and a domain name.

The operating system uses the computer name to identify itself on the network. On Linux systems, it is called the host name.

Option

Action

Use the virtual machine name

Select this option to use the virtual machine name. The computer name that vCenter Server creates is identical to the name of the virtual machine on which the guest operating system is running. If the name exceeds 63 characters, it is truncated.

Enter a name in the Clone/Deploy wizard

Select this option to be prompted to enter a name during cloning or deployment.

Enter a name

Enter a name.

The name can contain alphanumeric characters and a hyphen (-). It cannot contain a period (.), blank spaces, or special characters, and cannot contain digits only. Names are not case-sensitive.

(Optional) To ensure that the name is unique, select the Append a numeric value check box.

This action appends a hyphen followed by a numeric value to the virtual machine name. The name is truncated if it exceeds 63 characters when combined with the numeric value.

Generate a name using the custom application configured with vCenter Server

Optional: Enter a parameter that can be passed to the custom application.

On the Windows license page, provide licensing information for the Windows operating system and click Next.

Option

Action

For nonserver operating systems

Type the Windows product key for the new guest operating system.

For server operating systems

Type the Windows product key for the new guest operating system.

Select Include Server License Information.

Select either Per seat or Per server.

If you select Per server, enter the maximum number of simultaneous connections for the server to accept.

On the Set Administrator Password page, configure the administrator password for the virtual machine and click Next.

Enter a password for the administrator account and confirm the password by typing it again.

(Optional) Select the Automatically logon as Administrator check box to log users in to the guest operating system as Administrator, and select the number of times to log in automatically.

On the Time zone page, select the time zone for the virtual machine and click Next.

(Optional) On the Run Once page, specify commands to run the first time a user logs in to the guest operating system and click Next.

See the Microsoft Sysprep documentation for information about RunOnce commands.

On the Network page, select the type of network settings to apply to the guest operating system and click Next.

Select Use standard network settings so that vCenter Server configures all network interfaces from a DHCP server by using the default settings.

Select Manually select custom settings and configure each network interface yourself.

Select a network adapter from the list or add a new one.

For the selected NIC, click the vertical ellipsis icon and select Edit.

The Edit Network dialog box opens.

Click the IPv4 tab to configure the virtual machine to use IPv4 network.

You can configure all the settings at that stage or you can select the Prompt the user for an IPv4 address when the specification is used option. In that case, vCenter Server prompts for an IP address when you select to apply that customization specification during cloning or deployment. With that option, you can also configure the gateways during cloning or deployment.

Click the IPv6 tab to configure the virtual machine to use IPv6 network.

You can configure all the settings at that stage or you can select the Prompt the user for an address when the specification is used option. In that case, vCenter Server prompts for an IP address when you select to apply that customization specification during cloning or deployment. With that option, you can also configure the gateways during cloning or deployment.

Click the DNS tab to specify DNS server details.

Click WINS to specify primary and secondary WINS server information.

Click OK to close the Edit Network dialog box.

On the Set Workgroup or Domain page, select how the virtual machine participates in the network and click Next.

Option

Action

Workgroup

Enter a workgroup name. For example, MSHOME .

Windows Server Domain

Enter the domain name.

To add a computer to the specified domain, enter the user name and password for a user account that has permission.

On the Ready to complete page, review the details and click Finish to save your changes.

Before you can use vSphere ESXi Image Builder with the vSphere Web Client, you must verify that the service is enabled and running.

Log in to your vCenter Server system by using the vSphere Web Client.

On the vSphere Web Client Home page, click  Administration .

Under  System Configuration  click  Services .

Select  ImageBuilder Service , click the  Actions  menu, and select  Edit Startup Type .

On Windows, the vSphere ESXi Image Builder service is disabled. In the  Edit Startup Type  window, select  Manual  or  Automatic  to enable Auto Deploy.

On the vCenter Server Appliance, the vSphere ESXi Image Builder service by default is set to  Manual . If you want the service to start automatically upon OS startup, select  Automatic .

Procedure If you select the manual startup type, you must start the service manually upon OS startup every time you want to use the service.

(Optional)  Click the  Start the service  icon.

(Optional)  If you want to use vSphere ESXi Image Builder with thevSphere Web Client, log out of the vSphere Web Client and log in again.

The  Auto Deploy  icon is visible on the Home page of the vSphere Web Client.