VMware vSphere 4.x Install Configure Manage FAQ

Q1) Are we able to add odd number virtual CPUs to our virtual machines, for example 3 or 5 VCPU as compared to VI3 version when virtual SMP only supports 2 or 4 VCPU per virtual machine ?

Yes, we can now add odd number VCPU to our virtual machines.


Q2) What is the limitation for configuring VMware Fault Tolerance for a virtual machine ?

Virtual machine selected for VMware FT must be provisioned with thick disk and not thin disk, if it was provisioned with thin disk, there will be a prompt to inflate the existing disk size.


Q3) What is the disadvantage of configuring VM direct path I/O for a virtual machine ?

If we configured VM direct path I/O, the virtual machine gains significant performance improvement as it is provided direct access through the adapter, however, it loses it’s virtualization features and the adapter cannot be used by other virtual machines.


Q4) Does vSphere provide support for the currently version of VMware Site Recovery Manage version 1.0 ?

vSphere has does not support SRM version 1.0 at this present moment.


Q5) What is the benefit of using a Distributed vSwitch as compared to a Standard vSwitch ?

With a distributed virtual switch, the network statistics and policies of the virtual machine that has been vmotion to another ESX Server will migrate with the VM. This provides the ability for network vmotion and is useful for implementing inline intrusion detection systems and firewalls.


Q6) Does ESX 4 and ESXi 4 support jumbo frames and TSO ?

Yes, both ESX 4 and ESXi 4 provides support for jumbo frames as well as TSO, these can now be configured in the GUI as compared to VI3 where administrators could only do it via command lines.


Q7) What is the different between VMware Data Protection as compared to the traditional Vmware Consolidated Backup ?

VMware Data Protection supports all storage architecture for backup and restore via LAN and SAN. It also supports full, incremental and differential file level backup options.


Q8) What is the key driving factor for users adopting VMware vCenter Data Recovery ?

It’s an API that runs in a virtual machine within your vCenter, it provides agentless backup and can backup virtual machines even when they are being vmotion to a different host.


Q9) Can we perform Storage Vmotion now via the GUI inside vCenter ?

Yes, Storage Vmotion feature is now avaliable in the vSphere Client connected to vCenter Server. It provides full support for FC SAN and NFS.


Q10) When using vCenter Linked Mode feature, what are the functions that could be shared among the vCenters in this link ?

vCenter Linked Mode allows administrator to centrally manage all the vCenter within a single view, roles and licenses can be shared across the vCenters configured in a link.


Q11) Do I still require a Flexnet License Server if all my ESX Servers are ESX 4 and ESXi 4 ?

No, you no longer require a license server for the to manage the new ESX Servers. All licenses are managed within the vCenter Server.

Q12) If my customer has a hybrid environment where they still have ESX 3 and ESX 3.5, can vCenter communicate with the existing Flexnet License Server ?

Yes, vCenter can communicate with existing license servers so as to allow it to manage legacy ESX Servers. vCenter will pull the licenses for legacy hosts from the flexnet license server.


Q13) Why am I unable to hot add CPU and memory to virtual machine ?

You are required to enable this function under the virtual machine settings in order to use it. Therefore, it is advisable to enable it before you start your virtual machine for the very first time.


Q14) Is it true we can now use the new VMware Update Manager to upgrade our legacy ESX

Servers (For example: ESX 3.5) to ESX 4.0 version ?

Yes, the new VUM has the ability to upgrade your legacy ESX Server hosts for you. However, if you are upgrading a standalone host, you will be required to power off all virtual machines running on that host.


Q15) How come we are unable to use our existing VI Client to manage our ESX 4 and vCenter 4 ?

No, the legacy VI Client is unable to manage newer ESX Server Hosts and vCenter. You will need to install vSphere Client to manage newer ESX Server Hosts and vCenter as well as legacy ESX Hosts.


Q16) In vSphere, can we configure bidirectional CHAP authentication for iSCSI ?

Yes, we can now configure bidirectional CHAP authenticaton for iSCSI software. It is fully supported. Previously, we could only configure unidirectional CHAP authentication.


Q17) Do we still need to configure a Service Console port for iSCSI initiator ?

No, we no longer need a Service Console for software iSCSI initator. The vmkiscsid no longer runs in the Service Console. There have been improvements made to the new iSCSI stack in the kernel and also with the use of TCP/IP2 which has multi threading capabilities.


Q18) What is the maximum number of CPU and maximum amount of memory a virtual machine can scale ?

In vSphere, a virtual machine can now be configure with a maximum of 8 virtual CPUs and 255 GB of memory.

Q19) What is the maximum amount of logical CPUs and memory per ESX Server 4 host can scale ?

ESX Server 4 now supports a maximum of 64 logical CPUs and 1 TB of memory.


Q20) What actions allow us to configure thin disk provisioning for a virtual machine ?

When we create a new virtual machine, clone an existing virtual machine, clone a template or perform Storage Vmotion on an existing virtual machine.


Q21) What is the benefit of configuring thin disk provisioning as compared to thick disk

provisioning for a virtual machine ?

When we configure thin disk provisioning the virtual machine only uses the space that it requires and not the entire disk size, this allows the remaining unused space for other virtual machines. This enables us to do Storage Over-commitment and use the storage more efficiently.


Q22) Will my virtual machines still have connection if the virtual center that stores my Distributed vSwitch configuration goes down ?

Yes, this is because the Distributed vSwitch has an control plane which sits at the vCenter Server level and an I/O plane which are the form of hidden vSwitches sitting at the ESX level. Therefore, even if the vCenter goes down, virtual machines continue to have connectivity through the I/O plane at the ESX level.


Q23) What is the maximum number of ESX Hosts we can connect to a single distributed switch ?

We can connect up to 64 ESX hosts per distributed switch and vCenter 4 can support up a maximum of 16 distributed switches. Which means we can have up to 1024 hosts on these 16 distributed switches. Refer to “Configure Maximums” for more details.


Q24) What is the version of the 64 bit Service Console running in ESX 4 ?

The Service Console is a 2.6 linux kernel compatible with Red Hat Enterprise Linux 5.2 or CentOS 5.2 version.


Q25) What is the maximum number of uplinks or ports per ESX 4 or ESXi 4 Host ?

The maximum number of uplinks per ESX 4 or ESXi 4 Host is 32 uplinks. Refer to “Configure Maximums” for more details.


Q26) Can we install vCenter Server on a 64 bit Windows OS ?

Yes, vCenter Server can be installed on both 32-bit and 64-bit Windows OS. Refer to “Compatibility matrix” for more details.


Q27) Does ESX/ESXi 4 supports round robin multipathing policy ?

Yes besides fixed (preferred) and most recently used (MRU), ESX/ESXi 4 now supports round robin multipathing policy and it has to be configured on the storage level.


Q28) Can vCenter 4 support a cluster which includes ESX 3.x and ESX 4 hosts ?

Yes, we can cluster legacy ESX 3.x hosts and ESX 4 hosts together in the same cluster. vCenter will have to connect to the flexnet license server to manage the licenses for the legacy hosts. However, new features such as hot add and PCI pass through may not be avaliable to the VMs on legacy hosts. Refer to “Upgrade Guide” for more details.


Q29) When upgrading from virtual center 2.x to vCenter 4, is there downtime for the host and do we need to re add the ESX hosts back into the inventory ?

No, there’s no time for the hosts and existing hosts will remain in the inventory. However, there will be downtime for virtual center. Remember to backup the databases as during the upgrade process, the database schemas are changed and in the event of a upgrade failure, you will not be able to roll back and you will have to do a restore. Refer to “Upgrade Guide” for more details.


Q30) When we hot add memory to a powered on VM, will the swap file get dynamically increased ?

When we hot add memory to a powered on VM, the swap file size will get dynamically increase.


Q31) When we hot add memory to a powered on VM and the swap file get dynamically increased,

what happens if there is not enough disk space to meet the growing vswap file size ?

You will not be able to add memory to that VM that has not enough memory for the swap file to grow and you will receive an error.


Q32) Can we add USB controllers to our VM in ESX/ESXi 4 ?

Yes, we now have the ability to hot plug USB controller into our VMs while they are running. However, the usb device has to be connected to the ESX Server and not the client local machine.


Q33) When installing convertor plug-in, I get a 404 error and the installation halts ?

During installation of vCenter Convertor you will have to enter the FQDN instead of the IP address or netbios name as this may cause you to receive the 404 error when installing the vCenter convertor plug-in later.


Q34) Where is Distributed Power Management configured and what are the protocols it uses ?

DPM is configured and managed at the DRS cluster level. It uses IPMI, ILO and Wake On LAN protocols. DRS can use DPM to put underutilized hosts into standby modes to save power consumption.


Q35) What is new with vCenter 4 user access and role management as compared to the virtual center 2.5 ?

vCenter 4 allows us the ability to assign administrators to inventory objects such as networks and datastores which were not available with the previous virtual center version.


Q36) What are the new tasks we can schedule in vCenter 4 task scheduler ?

vCenter 4 task scheduler allows us the ability to schedule a task to increase the resources in a resource pool or virtual machine. This would be good to cater to the needs of virtual machines that will require additional ad-hoc resources such as finance department doing month end closing which may result in resources surge on their machines.


Q37) How does VMware HA on an ESXi Server sends out heart beat if ESXi does not have a service console ?

VMware HA clusters configured for ESXi Servers uses the vmkernel present on all ESXi Servers to send and receive heart beats. Whereas, on ESX Servers the heartbeat is send and receive through the service console. Therefore, we may not want to cluster ESX and ESXi Servers together in the same cluster.


Q38) Can we create a cluster with ESX and ESXi Servers ?

Yes. However, VMware HA may not work as both servers uses different port groups to send out heart beats. Vmotion and DRS may still work. This is not a supported practise.


Q39) What is the limitation for configuring VMware Fault Tolerance for a virtual machine ?

Virtual machine selected for VMware FT must be provisioned with thick disk and not thin disk, if it was provisioned with thin disk, there will be a prompt to inflate the existing disk size.


Q40) How can I grow an existing VMFS LUN without creating an extent or physical partition ?

We can use the grow function to grow an existing VMFS LUN. If the LUN is out of space, first we must get the storage administrator to grow the same LUN on the storage level with storage array management utilities then within the vCenter Server, we can then select the LUN and grow it.


Q41) How come the hot add CPU and hot add memory option is greyed out for my VM ?

This feature is currently available only on supported guest OS such as Windows Server 2003 enterprise and

Windows 2008 datacenter edition. The type of license also plays a part on the availability of this feature to the VM.


Q42) What does the channel number stands for in vmhba#:T:C:L?

The only real example that I’ve seen in vSphere so far, is the software iSCSI initiator. If you give the VMkernel multiple VMkernel ports, and each port can reach (over its own subnet) different targets, they are listed with different “channel” numbers, to indicate whether they use the first VMkernel port, the second or the third.


Q43) Can we install VMware Consolidated Backup VCB in a virtual machine ?

Yes, VCB can now be installed in a VM and it can be use to backup VMs running on iSCSI and NFS. However,if you wish to backup VMs whose files reside on an FC San LUN, VCB must be installed on a physical machine.


Q44) Does VMware View 3 work with VMware vSphere 4 ?

No, currently VMware View 3 is only supported on VI 3.5 infrastructure and it is not supported to work with vSphere 4 environment.


Q45) Is the Service Console root file system still running on ext3 file system ?

No, the SC root file system is now running on VMDK and this is automatically created during initial installation of ESX Servers.


Q46) Is it possible to configure VMware Update Manager 4 to point to WSUS to grab windows updates ?

No, this is not possible as the VUM Server is unable to communicate with the WSUS Server.


Q47) Can vCenter 4 perform Storage Vmotion on a legacy ESX 3.x Host and convert the VM virtual disk from thick to thin disk ?

Yes, vCenter 4 is able to convert a VM’s virtual disk from thick to thin using storage vmotion. Refer to this “ESX 3.x and vCenter 4 SVmotion” for more detail discussion.


Q48) I understand that Oracle databases licensed by per CPU, how does that translate to the number of license I have to purchase if I port it over to VM ?

In order for you to run your Oracle DB within a VM on that ESX Server, you have to purchase license for each physical CPU on that ESX Server box. Refer to this “Oracle Licensing Per Processor” for more detail discussion.


Q49) How come there is no standalone boot CD for VMware Convertor 4.0 for me to download for use for cold cloning ?

VMware vCenter Converter Standalone 4.0.1 does not support cold cloning, you must use an earlier Converter edition boot CD 3.0.x Enterprise Edition. Refer to this “VMware Convertor User Guide” for more information.


Q50) When we convert a VM from thin disk to thick disk, which state must the VM be in to perform the request ?

The VM must be in the powered off state in order to be converted from thin to thick disk.


Q51) What is the default multipathing policy for ESX 4 ?

The hypervisor determines whether to use MRU or Fixed based on the type of arrays it detects. If array is active\passive, it would be treated as MRU. If array is active\active, it would be treated as fixed. Refer to “Multipathing Policies in ESX 4” for more details.


Q52) What is the difference between Enhanced vmxnet and vmxnet3 ?

Vmxnet3 is an improved version of enhanced vmxnet, some benefits and improvements are MSI/MSI-X support, Side Scaling, checksum and TCP Segmentation Offloading (TSO) over IPv6, off-loading and Large TX/RX ring sizes. Refer to “Vmxnet3 tips and tricks” for more details.


Q53) When we replicate the LUNs over resignaturing only occurs for VMFS LUNs and not RDM, how do we get the replicated RDM to work ?

You can replicate the RDM to a new array, but the mapping file that is configured on the vm itself will no longer be pointing to the same location it was previously, so the RDM has to be re-mapped to the VM in a DR scenario.


Q54) After installing plug-in inside the VC, I am unable to enable the plug-in and it always shows as disabled.

Go to services.msc ensure that the Virtual Center Management Webservices is running and then relogin the vSphere Client and enable the plug-in.


Q55) What is the difference between ephemeral and dynamic binding on a distributed virtual switch ?

Ephemeral a new port on every power-on. The port is destroyed when the VM disconnects from the port. Dynamic assign a port when the VM is powered on, it uses a concept similar to DHCP in that if the same port is available then it will renew that one. Refer to “Networking Deep Dive” for more details.


Q56) What is the difference between a thick virtual disk and eager zeroed thick virtual disk ?

Thick virtual disk does not format the VMDK at the time of deployment. This means that data, which needs to be written, must pause while the blocks required to store the data are zeroed out. An eager zeroed thick virtual disk actually formats all of its data blocks at the time of deployment.


Q57) What kind of permissions do we need to provide when configuring a NAS Server ?

We need to configure permission for the administrator group account rights on the NAS Server so that the ESX Server can access the NAS Server.


Q58) Storage View tabs in the SAN storage datastore is blank and does not show anything ?

Start the vCenter Mount Service and virtual disk service, then restart the vCenter Server service on the Windows OS. Then click on refresh for the storage view tabs.


Q59) Can we migrate VMs running on ESX host with VMware Hardware Version 7 to ESX host with VMware Hardware Version 4 ?

No we cannot migrate VMs running on hardware version 7 back to hardware version 4. VMware hardware version 7 only exists on ESX4 and greater. However, it is possible to migrate VMs running on ESX host with hardware version 4 to ESX host running on hardware version 7.


Q60) Does VMware have an online page where we can search for all the technical white papers ?

Yes. Please kindly refer to “Technical Resource Center” for more information.


Q61) Does VCB supports Windows Server 2008 ?

VCB version 1.5 supports Windows Server 2008. Refer to “VCB 1.5 Update 1” release notes for more information.

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