Appendix A. Reference: Settings in Administration Portal and VM Portal Windows
A.1. Explanation of Settings in the New Virtual Machine and Edit Virtual Machine Windows
A.1.1. Virtual Machine General Settings Explained
The following table details the options available on the General tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Description | Power cycle required? |
|---|---|---|
| Cluster | The name of the host cluster to which the virtual machine is attached. Virtual machines are hosted on any physical machine in that cluster in accordance with policy rules. | Yes. Cross-cluster migration is for emergency use only. Moving clusters requires the virtual machine to be down. |
| Template |
The template on which the virtual machine is based. This field is set to
The version name is displayed as
When the virtual machine is stateless, there is an option to select the | Not applicable. This setting is for provisioning new virtual machines only. |
| Operating System | The operating system. Valid values include a range of Red Hat Enterprise Linux and Windows variants. | Yes. Potentially changes the virtual hardware. |
| Instance Type | The instance type on which the virtual machine’s hardware configuration can be based. This field is set to Custom by default, which means the virtual machine is not connected to an instance type. The other options available from this drop down menu are Large, Medium, Small, Tiny, XLarge, and any custom instance types that the Administrator has created. Other settings that have a chain link icon next to them are pre-filled by the selected instance type. If one of these values is changed, the virtual machine will be detached from the instance type and the chain icon will appear broken. However, if the changed setting is restored to its original value, the virtual machine will be reattached to the instance type and the links in the chain icon will rejoin. NOTE: Support for instance types is now deprecated, and will be removed in a future release. | Yes. |
| Optimized for | The type of system for which the virtual machine is to be optimized. There are three options: Server, Desktop, and High Performance; by default, the field is set to Server. Virtual machines optimized to act as servers have no sound card, use a cloned disk image, and are not stateless. Virtual machines optimized to act as desktop machines do have a sound card, use an image (thin allocation), and are stateless. Virtual machines optimized for high performance have a number of configuration changes. See Configuring High Performance Virtual Machines Templates and Pools. | Yes. |
| Name | The name of the virtual machine. The name must be a unique name within the data center and must not contain any spaces, and must contain at least one character from A-Z or 0-9. The maximum length of a virtual machine name is 255 characters. The name can be reused in different data centers in the environment. | Yes. |
| VM ID |
The virtual machine ID. The virtual machine’s creator can set a custom ID for that virtual machine. The custom ID must contain only numbers, in the format, If no ID is specified during creation a UUID will be automatically assigned. For both custom and automatically-generated IDs, changes are not possible after virtual machine creation. | Yes. |
| Description | A meaningful description of the new virtual machine. | No. |
| Comment | A field for adding plain text human-readable comments regarding the virtual machine. | No. |
| Affinity Labels | Add or remove a selected Affinity Label. | No. |
| Stateless | Select this check box to run the virtual machine in stateless mode. This mode is used primarily for desktop virtual machines. Running a stateless desktop or server creates a new COW layer on the virtual machine hard disk image where new and changed data is stored. Shutting down the stateless virtual machine deletes the new COW layer which includes all data and configuration changes, and returns the virtual machine to its original state. Stateless virtual machines are useful when creating machines that need to be used for a short time, or by temporary staff. | Not applicable. |
| Start in Pause Mode | Select this check box to always start the virtual machine in pause mode. This option is suitable for virtual machines which require a long time to establish a SPICE connection; for example, virtual machines in remote locations. | Not applicable. |
| Delete Protection | Select this check box to make it impossible to delete the virtual machine. It is only possible to delete the virtual machine if this check box is not selected. | No. |
| Sealed | Select this check box to seal the created virtual machine. This option eliminates machine-specific settings from virtual machines that are provisioned from the template. For more information about the sealing process, see Sealing a Windows Virtual Machine for Deployment as a Template | No. |
| Instance Images | Click Attach to attach a floating disk to the virtual machine, or click Create to add a new virtual disk. Use the plus and minus buttons to add or remove additional virtual disks. Click to change the configuration of a virtual disk that has already been attached or created. | No. |
| Instantiate VM network interfaces by picking a vNIC profile. | Add a network interface to the virtual machine by selecting a vNIC profile from the nic1 drop-down list. Use the plus and minus buttons to add or remove additional network interfaces. | No. |
A.1.2. Virtual Machine System Settings Explained
CPU Considerations
For non-CPU-intensive workloads, you can run virtual machines with a total number of processor cores greater than the number of cores in the host (the number of processor cores for a single virtual machine must not exceed the number of cores in the host). The following benefits can be achieved:
- You can run a greater number of virtual machines, which reduces hardware requirements.
- You can configure virtual machines with CPU topologies that are otherwise not possible, such as when the number of virtual cores is between the number of host cores and the number of host threads.
- For best performance, and especially for CPU-intensive workloads, you should use the same topology in the virtual machine as in the host, so the host and the virtual machine expect the same cache usage. When the host has hyperthreading enabled, QEMU treats the host’s hyperthreads as cores, so the virtual machine is not aware that it is running on a single core with multiple threads. This behavior might impact the performance of a virtual machine, because a virtual core that actually corresponds to a hyperthread in the host core might share a single cache with another hyperthread in the same host core, while the virtual machine treats it as a separate core.
The following table details the options available on the System tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Description | Power cycle required? |
|---|---|---|
| Memory Size | The amount of memory assigned to the virtual machine. When allocating memory, consider the processing and storage needs of the applications that are intended to run on the virtual machine. | If OS supports hotplugging, no. Otherwise, yes. |
| Maximum Memory | The maximum amount of memory that can be assigned to the virtual machine. Maximum guest memory is also constrained by the selected guest architecture and the cluster compatibility level. | If OS supports hotplugging, no. Otherwise, yes. |
| Total Virtual CPUs | The processing power allocated to the virtual machine as CPU Cores. For high performance, do not assign more cores to a virtual machine than are present on the physical host. | If OS supports hotplugging, no. Otherwise, yes. |
| Virtual Sockets | The number of CPU sockets for the virtual machine. Do not assign more sockets to a virtual machine than are present on the physical host. | If OS supports hotplugging, no. Otherwise, yes. |
| Cores per Virtual Socket | The number of cores assigned to each virtual socket. | If OS supports hotplugging, no. Otherwise, yes. |
| Threads per Core | The number of threads assigned to each core. Increasing the value enables simultaneous multi-threading (SMT). IBM POWER8 supports up to 8 threads per core. For x86 and x86_64 (Intel and AMD) CPU types, the recommended value is 1, unless you want to replicate the exact host topology, which you can do using CPU pinning. For more information, see Pinning CPU. | If OS supports hotplugging, no. Otherwise, yes. |
| Chipset/Firmware Type | Specifies the chipset and firmware type. Defaults to the cluster’s default chipset and firmware type. Options are:
For more information, see UEFI and the Q35 chipset in the Administration Guide. | Yes. |
| Custom Emulated Machine | This option allows you to specify the machine type. If changed, the virtual machine will only run on hosts that support this machine type. Defaults to the cluster’s default machine type. | Yes. |
| Custom CPU Type | This option allows you to specify a CPU type. If changed, the virtual machine will only run on hosts that support this CPU type. Defaults to the cluster’s default CPU type. | Yes. |
| Hardware Clock Time Offset | This option sets the time zone offset of the guest hardware clock. For Windows, this should correspond to the time zone set in the guest. Most default Linux installations expect the hardware clock to be GMT+00:00. | Yes. |
| Custom Compatibility Version | The compatibility version determines which features are supported by the cluster, as well as, the values of some properties and the emulated machine type. By default, the virtual machine is configured to run in the same compatibility mode as the cluster as the default is inherited from the cluster. In some situations the default compatibility mode needs to be changed. An example of this is if the cluster has been updated to a later compatibility version but the virtual machines have not been restarted. These virtual machines can be set to use a custom compatibility mode that is older than that of the cluster. See Changing the Cluster Compatibility Version in the Administration Guide for more information. | Yes. |
| Serial Number Policy | Override the system-level and cluster-level policies for assigning a serial numbers to virtual machines. Apply a policy that is unique to this virtual machine:
| Yes. |
| Custom Serial Number | Specify the custom serial number to apply to this virtual machine. | Yes. |
A.1.3. Virtual Machine Initial Run Settings Explained
The following table details the options available on the Initial Run tab of the New Virtual Machine and Edit Virtual Machine windows. The settings in this table are only visible if the Use Cloud-Init/Sysprep check box is selected, and certain options are only visible when either a Linux-based or Windows-based option has been selected in the Operating System list in the General tab, as outlined below.
This table does not include information on whether a power cycle is required because the settings apply to the virtual machine’s initial run; the virtual machine is not running when you configure these settings.
| Field Name | Operating System | Description |
|---|---|---|
| Use Cloud-Init/Sysprep | Linux, Windows | This check box toggles whether Cloud-Init or Sysprep will be used to initialize the virtual machine. |
| VM Hostname | Linux, Windows | The host name of the virtual machine. |
| Domain | Windows | The Active Directory domain to which the virtual machine belongs. |
| Organization Name | Windows | The name of the organization to which the virtual machine belongs. This option corresponds to the text field for setting the organization name displayed when a machine running Windows is started for the first time. |
| Active Directory OU | Windows | The organizational unit in the Active Directory domain to which the virtual machine belongs. |
| Configure Time Zone | Linux, Windows | The time zone for the virtual machine. Select this check box and select a time zone from the Time Zone list. |
| Admin Password | Windows | The administrative user password for the virtual machine. Click the disclosure arrow to display the settings for this option.
|
| Authentication | Linux | The authentication details for the virtual machine. Click the disclosure arrow to display the settings for this option.
|
| Custom Locale | Windows |
Custom locale options for the virtual machine. Locales must be in a format such as
|
| Networks | Linux | Network-related settings for the virtual machine. Click the disclosure arrow to display the settings for this option.
|
| Custom Script | Linux |
Custom scripts that will be run on the virtual machine when it starts. The scripts entered in this field are custom YAML sections that are added to those produced by the Manager, and allow you to automate tasks such as creating users and files, configuring |
| Sysprep | Windows | A custom Sysprep definition. The definition must be in the format of a complete unattended installation answer file. You can copy and paste the default answer files in the /usr/share/ovirt-engine/conf/sysprep/ directory on the machine on which the Red Hat Virtualization Manager is installed and alter the fields as required. See Templates for more information. |
| Ignition 2.3.0 | Red Hat Enterprise Linux CoreOS | When Red Hat Enterprise Linux CoreOS is selected as Operating System, this check box toggles whether Ignition will be used to initialize the virtual machine. |
A.1.4. Virtual Machine Console Settings Explained
The following table details the options available on the Console tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Description | Power cycle required? |
|---|---|---|
| Graphical Console Section | A group of settings. | Yes. |
| Headless Mode | Select this check box if you do not a require a graphical console for the virtual machine. When selected, all other fields in the Graphical Console section are disabled. In the VM Portal, the Console icon in the virtual machine’s details view is also disabled. Important See Configuring Headless Machines for more details and prerequisites for using headless mode. | Yes. |
| Video Type | Defines the graphics device. QXL is the default and supports both graphic protocols. VGA supports only the VNC protocol. | Yes. |
| Graphics protocol | Defines which display protocol to use. SPICE is the default protocol. VNC is an alternative option. To allow both protocols select SPICE + VNC. | Yes. |
| VNC Keyboard Layout | Defines the keyboard layout for the virtual machine. This option is only available when using the VNC protocol. | Yes. |
| USB enabled | Defines SPICE USB redirection. This check box is not selected by default. This option is only available for virtual machines using the SPICE protocol:
| Yes. |
| Console Disconnect Action | Defines what happens when the console is disconnected. This is only relevant with SPICE and VNC console connections. This setting can be changed while the virtual machine is running but will not take effect until a new console connection is established. Select either:
| No. |
| Monitors | The number of monitors for the virtual machine. This option is only available for virtual desktops using the SPICE display protocol. You can choose 1, 2 or 4. Note that multiple monitors are not supported for Windows systems with WDDMDoD drivers. | Yes. |
| Smartcard Enabled | Smart cards are an external hardware security feature, most commonly seen in credit cards, but also used by many businesses as authentication tokens. Smart cards can be used to protect Red Hat Virtualization virtual machines. Select or clear the check box to activate and deactivate Smart card authentication for individual virtual machines. | Yes. |
| Single Sign On method | Enabling Single Sign On allows users to sign into the guest operating system when connecting to a virtual machine from the VM Portal using the Guest Agent.
| If you select Use Guest Agent, no. Otherwise, yes. |
| Disable strict user checking | Click the Advanced Parameters arrow and select the check box to use this option. With this option selected, the virtual machine does not need to be rebooted when a different user connects to it. By default, strict checking is enabled so that only one user can connect to the console of a virtual machine. No other user is able to open a console to the same virtual machine until it has been rebooted. The exception is that a SuperUser can connect at any time and replace a existing connection. When a SuperUser has connected, no normal user can connect again until the virtual machine is rebooted. Disable strict checking with caution, because you can expose the previous user’s session to the new user. | No. |
| Soundcard Enabled | A sound card device is not necessary for all virtual machine use cases. If it is for yours, enable a sound card here. | Yes. |
| Enable SPICE file transfer | Defines whether a user is able to drag and drop files from an external host into the virtual machine’s SPICE console. This option is only available for virtual machines using the SPICE protocol. This check box is selected by default. | No. |
| Enable SPICE clipboard copy and paste | Defines whether a user is able to copy and paste content from an external host into the virtual machine’s SPICE console. This option is only available for virtual machines using the SPICE protocol. This check box is selected by default. | No. |
| Serial Console Section | A group of settings. | |
| Enable VirtIO serial console | The VirtIO serial console is emulated through VirtIO channels, using SSH and key pairs, and allows you to access a virtual machine’s serial console directly from a client machine’s command line, instead of opening a console from the Administration Portal or the VM Portal. The serial console requires direct access to the Manager, since the Manager acts as a proxy for the connection, provides information about virtual machine placement, and stores the authentication keys. Select the check box to enable the VirtIO console on the virtual machine. Requires a firewall rule. See Opening a Serial Console to a Virtual Machine. | Yes. |
A.1.5. Virtual Machine Host Settings Explained
The following table details the options available on the Host tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Sub-element | Description | Power cycle required? |
|---|---|---|---|
| Start Running On | Defines the preferred host on which the virtual machine is to run. Select either:
| No. The virtual machine can migrate to that host while running. | |
| CPU options | Pass-Through Host CPU | When selected, allows virtual machines to use the host’s CPU flags. When selected, Migration Options is set to Allow manual migration only. | Yes |
| Migrate only to hosts with the same TSC frequency | When selected, this virtual machine can only be migrated to a host with the same TSC frequency. This option is only valid for High Performance virtual machines. | Yes | |
| Migration Options | Migration mode | Defines options to run and migrate the virtual machine. If the options here are not used, the virtual machine will run or migrate according to its cluster’s policy.
| No |
| Migration policy | Defines the migration convergence policy. If the check box is left unselected, the host determines the policy.
| No | |
| Enable migration encryption | Allows the virtual machine to be encrypted during migration.
| No | |
| Parallel Migrations | Allows you to specify whether and how many parallel migration connections to use.
| ||
| Number of VM Migration Connections | This setting is only available when Custom is selected. The preferred number of custom parallel migrations, between 2 and 255. | ||
| Configure NUMA | NUMA Node Count | The number of virtual NUMA nodes available in a host that can be assigned to the virtual machine. | No |
| NUMA Pinning | Opens the NUMA Topology window. This window shows the host’s total CPUs, memory, and NUMA nodes, and the virtual machine’s virtual NUMA nodes. You can manually pin virtual NUMA nodes to host NUMA nodes by clicking and dragging each vNUMA from the box on the right to a NUMA node on the left. You can also set Tune Mode for memory allocation: Strict - Memory allocation will fail if the memory cannot be allocated on the target node. Preferred - Memory is allocated from a single preferred node. If sufficient memory is not available, memory can be allocated from other nodes. Interleave - Memory is allocated across nodes in a round-robin algorithm. If you define NUMA pinning, Migration Options is set to Allow manual migration only. | Yes |
A.1.6. Virtual Machine High Availability Settings Explained
The following table details the options available on the High Availability tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Description | Power cycle required? |
|---|---|---|
| Highly Available | Select this check box if the virtual machine is to be highly available. For example, in cases of host maintenance, all virtual machines are automatically live migrated to another host. If the host crashes and is in a non-responsive state, only virtual machines with high availability are restarted on another host. If the host is manually shut down by the system administrator, the virtual machine is not automatically live migrated to another host. Note that this option is unavailable for virtual machines defined as Server or Desktop if the Migration Options setting in the Hosts tab is set to Do not allow migration. For a virtual machine to be highly available, it must be possible for the Manager to migrate the virtual machine to other available hosts as necessary. However, for virtual machines defined as High Performance, you can define high availability regardless of the Migration Options setting. | Yes. |
| Target Storage Domain for VM Lease | Select the storage domain to hold a virtual machine lease, or select No VM Lease to disable the functionality. When a storage domain is selected, it will hold a virtual machine lease on a special volume that allows the virtual machine to be started on another host if the original host loses power or becomes unresponsive. This functionality is only available on storage domain V4 or later. Note If you define a lease, the only Resume Behavior available is KILL. | Yes. |
| Resume Behavior | Defines the desired behavior of a virtual machine that is paused due to storage I/O errors, once a connection with the storage is reestablished. You can define the desired resume behavior even if the virtual machine is not highly available. The following options are available:
| No. |
| Priority for Run/Migration queue | Sets the priority level for the virtual machine to be migrated or restarted on another host. | No. |
| Watchdog | Allows users to attach a watchdog card to a virtual machine. A watchdog is a timer that is used to automatically detect and recover from failures. Once set, a watchdog timer continually counts down to zero while the system is in operation, and is periodically restarted by the system to prevent it from reaching zero. If the timer reaches zero, it signifies that the system has been unable to reset the timer and is therefore experiencing a failure. Corrective actions are then taken to address the failure. This functionality is especially useful for servers that demand high availability. Watchdog Model: The model of watchdog card to assign to the virtual machine. At current, the only supported model is i6300esb. Watchdog Action: The action to take if the watchdog timer reaches zero. The following actions are available:
| Yes. |
A.1.7. Virtual Machine Resource Allocation Settings Explained
The following table details the options available on the Resource Allocation tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Sub-element | Description | Power cycle required? |
|---|---|---|---|
| CPU Allocation | CPU Profile | The CPU profile assigned to the virtual machine. CPU profiles define the maximum amount of processing capability a virtual machine can access on the host on which it runs, expressed as a percent of the total processing capability available to that host. CPU profiles are defined for a cluster, based on quality of service entries created for data centers. | No. |
| CPU Shares | Allows users to set the level of CPU resources a virtual machine can demand relative to other virtual machines.
| No. | |
| CPU Pinning Policy |
| No. | |
| CPU Pinning topology |
Enables the virtual machine’s virtual CPU (vCPU) to run on a specific physical CPU (pCPU) in a specific host. The syntax of CPU pinning is
The CPU Pinning Topology is populated automatically when In order to pin a virtual machine to a host, you must also select the following on the Host tab:
If CPU pinning is set and you change Start Running On: Specific a CPU pinning topology will be lost window appears when you click . When defined, Migration Options in the Hosts tab is set to Allow manual migration only. | Yes. | |
| Memory Allocation | Physical Memory Guaranteed | The amount of physical memory guaranteed for this virtual machine. Should be any number between 0 and the defined memory for this virtual machine. | If lowered, yes. Otherwise, no. |
| Memory Balloon Device Enabled | Enables the memory balloon device for this virtual machine. Enable this setting to allow memory overcommitment in a cluster. Enable this setting for applications that allocate large amounts of memory suddenly but set the guaranteed memory to the same value as the defined memory.Use ballooning for applications and loads that slowly consume memory, occasionally release memory, or stay dormant for long periods of time, such as virtual desktops. See Optimization Settings Explained in the Administration Guide for more information. | Yes. | |
| Trusted Platform Module | TPM Device Enabled | Enables the addition of an emulated Trusted Platform Module (TPM) device. Select this check box to add an emulated Trusted Platform Module device to a virtual machine. TPM devices can only be used on x86_64 machines with UEFI firmware and PowerPC machines with pSeries firmware installed. See Adding Trusted Platform Module devices for more information. | Yes. |
| IO Threads | IO Threads Enabled | Enables IO threads. Select this check box to improve the speed of disks that have a VirtIO interface by pinning them to a thread separate from the virtual machine’s other functions. Improved disk performance increases a virtual machine’s overall performance. Disks with VirtIO interfaces are pinned to an IO thread using a round-robin algorithm. | Yes. |
| Queues | Multi Queues Enabled | Enables multiple queues. This check box is selected by default. It creates up to four queues per vNIC, depending on how many vCPUs are available. It is possible to define a different number of queues per vNIC by creating a custom property as follows:
where other-nic-properties is a semicolon-separated list of pre-existing NIC custom properties. | Yes. |
| VirtIO-SCSI Enabled | Allows users to enable or disable the use of VirtIO-SCSI on the virtual machines. | Not applicable. | |
| VirtIO-SCSI Multi Queues Enabled | The VirtIO-SCSI Multi Queues Enabled option is only available when VirtIO-SCSI Enabled is selected. Select this check box to enable multiple queues in the VirtIO-SCSI driver. This setting can improve I/O throughput when multiple threads within the virtual machine access the virtual disks. It creates up to four queues per VirtIO-SCSI controller, depending on how many disks are connected to the controller and how many vCPUs are available. | Not applicable. | |
| Storage Allocation | The Storage Allocation option is only available when the virtual machine is created from a template. | Not applicable. | |
| Thin | Provides optimized usage of storage capacity. Disk space is allocated only as it is required. When selected, the format of the disks will be marked as QCOW2 and you will not be able to change it. | Not applicable. | |
| Clone | Optimized for the speed of guest read and write operations. All disk space requested in the template is allocated at the time of the clone operation. Possible disk formats are QCOW2 or Raw. | Not applicable. | |
| Disk Allocation | The Disk Allocation option is only available when you are creating a virtual machine from a template. | Not applicable. | |
| Alias | An alias for the virtual disk. By default, the alias is set to the same value as that of the template. | Not applicable. | |
| Virtual Size | The total amount of disk space that the virtual machine based on the template can use. This value cannot be edited, and is provided for reference only. | Not applicable. | |
| Format | The format of the virtual disk. The available options are QCOW2 and Raw. When Storage Allocation is Thin, the disk format is QCOW2. When Storage Allocation is Clone, select QCOW2 or Raw. | Not applicable. | |
| Target | The storage domain on which the virtual disk is stored. By default, the storage domain is set to the same value as that of the template. | Not applicable. | |
| Disk Profile | The disk profile to assign to the virtual disk. Disk profiles are created based on storage profiles defined in the data centers. For more information, see Creating a Disk Profile. | Not applicable. |
A.1.8. Virtual Machine Boot Options Settings Explained
The following table details the options available on the Boot Options tab of the New Virtual Machine and Edit Virtual Machine windows
| Field Name | Description | Power cycle required? |
|---|---|---|
| First Device | After installing a new virtual machine, the new virtual machine must go into Boot mode before powering up. Select the first device that the virtual machine must try to boot:
| Yes. |
| Second Device | Select the second device for the virtual machine to use to boot if the first device is not available. The first device selected in the previous option does not appear in the options. | Yes. |
| Attach CD | If you have selected CD-ROM as a boot device, select this check box and select a CD-ROM image from the drop-down menu. The images must be available in the ISO domain. | Yes. |
| Enable menu to select boot device | Enables a menu to select the boot device. After the virtual machine starts and connects to the console, but before the virtual machine starts booting, a menu displays that allows you to select the boot device. This option should be enabled before the initial boot to allow you to select the required installation media. | Yes. |
A.1.9. Virtual Machine Random Generator Settings Explained
The following table details the options available on the Random Generator tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Description | Power cycle required? |
|---|---|---|
| Random Generator enabled | Selecting this check box enables a paravirtualized Random Number Generator PCI device (virtio-rng). This device allows entropy to be passed from the host to the virtual machine in order to generate a more sophisticated random number. Note that this check box can only be selected if the RNG device exists on the host and is enabled in the host’s cluster. | Yes. |
| Period duration (ms) | Specifies the duration of the RNG’s "full cycle" or "full period" in milliseconds. If omitted, the libvirt default of 1000 milliseconds (1 second) is used. If this field is filled, Bytes per period must be filled also. | Yes. |
| Bytes per period | Specifies how many bytes are permitted to be consumed per period. | Yes. |
| Device source: | The source of the random number generator. This is automatically selected depending on the source supported by the host’s cluster.
| Yes. |
A.1.10. Virtual Machine Custom Properties Settings Explained
The following table details the options available on the Custom Properties tab of the New Virtual Machine and Edit Virtual Machine windows.
| Field Name | Description | Recommendations and Limitations | Power cycle required? |
|---|---|---|---|
| sndbuf | Enter the size of the buffer for sending the virtual machine’s outgoing data over the socket. Default value is 0. | - | Yes |
| hugepages | Enter the huge page size in KB. |
| Yes |
| vhost |
Disables vhost-net, which is the kernel-based virtio network driver on virtual network interface cards attached to the virtual machine. To disable vhost, the format for this property is This will explicitly start the virtual machine without the vhost-net setting on the virtual NIC attached to LogicalNetworkName. | vhost-net provides better performance than virtio-net, and if it is present, it is enabled on all virtual machine NICs by default. Disabling this property makes it easier to isolate and diagnose performance issues, or to debug vhost-net errors; for example, if migration fails for virtual machines on which vhost does not exist. | Yes |
| sap_agent | Enables SAP monitoring on the virtual machine. Set to true or false. | - | Yes |
| viodiskcache | Caching mode for the virtio disk. writethrough writes data to the cache and the disk in parallel, writeback does not copy modifications from the cache to the disk, and none disables caching. | In order to ensure data integrity in the event of a fault in storage, in the network, or in a host during migration, do not migrate virtual machines with viodiskcache enabled, unless virtual machine clustering or application-level clustering is also enabled. | Yes |
| scsi_hostdev | Optionally, if you add a SCSI host device to a virtual machine, you can specify the optimal SCSI host device driver. For details, see Adding Host Devices to a Virtual Machine.
| If you are not sure, try scsi_hd. | Yes |
Increasing the value of the sndbuf custom property results in increased occurrences of communication failure between hosts and unresponsive virtual machines.
A.1.11. Virtual Machine Icon Settings Explained
You can add custom icons to virtual machines and templates. Custom icons can help to differentiate virtual machines in the VM Portal. The following table details the options available on the Icon tab of the New Virtual Machine and Edit Virtual Machine windows.
This table does not include information on whether a power cycle is required because these settings apply to the virtual machine’s appearance in the Administration portal, not to its configuration.
| Button Name | Description |
|---|---|
| Upload | Click this button to select a custom image to use as the virtual machine’s icon. The following limitations apply:
|
| Power cycle required? | Use default |
A.1.12. Virtual Machine Foreman/Satellite Settings Explained
The following table details the options available on the Foreman/Satellite tab of the New Virtual Machine and Edit Virtual Machine windows
| Field Name | Description | Power cycle required? |
|---|---|---|
| Provider | If the virtual machine is running Red Hat Enterprise Linux and the system is configured to work with a Satellite server, select the name of the Satellite from the list. This enables you to use Satellite’s content management feature to display the relevant Errata for this virtual machine. See Configuring Satellite Errata for more details. | Yes. |
