ESX and ESXi Server Comparison September 17, 2011
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| ESXi – Free License(ESX not available without VI) | VI Foundation(with ESX or ESXi) | VI Standard(with ESX or ESXi) | VI Enterprise(with ESX or ESXi) | |
| Core hypervisor functionality | Yes | Yes | Yes | Yes |
| Virtual SMP | Yes | Yes | Yes | Yes |
| VMFS | Yes | Yes | Yes | Yes |
| VirtualCenter Agent | Yes | Yes | Yes | |
| Update Manager | Yes | Yes | Yes | |
| Consolidated Backup | Yes | Yes | Yes | |
| High Availability | Yes | Yes | ||
| VMotion | Yes | |||
| Storage VMotion | Yes | |||
| DRS | Yes | |||
| DPM | Yes |
ESX and ESXi Server Comparison September 6, 2011
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There are other feature differences and also licensing and upgrade path differences as shown below.
VMware KB ESX ESXi Comparison
| ESXi – Free License
(ESX not available without VI) |
VI Foundation
(with ESX or ESXi) |
VI Standard
(with ESX or ESXi) |
VI Enterprise
(with ESX or ESXi) |
|
| Core hypervisor functionality | Yes | Yes | Yes | Yes |
| Virtual SMP | Yes | Yes | Yes | Yes |
| VMFS | Yes | Yes | Yes | Yes |
| VirtualCenter Agent | Yes | Yes | Yes | |
| Update Manager | Yes | Yes | Yes | |
| Consolidated Backup | Yes | Yes | Yes | |
| High Availability | Yes | Yes | ||
| VMotion | Yes | |||
| Storage VMotion | Yes | |||
| DRS | Yes | |||
| DPM | Yes |
Why vCenter Server Heartbeat? August 23, 2011
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| Host Replication | Heartbeat | |
| Hardware & OS failures | Yes | Yes |
| Configuration Agnostic | Yes | Yes |
| WAN failover | Partial | Yes |
| Complexity | Medium-High | Low |
| Protects vCenter Server components | No | Yes |
| Network failures | No | Yes |
Impact of Vmware vCenter Server Downtime August 23, 2011
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| Component | Impact Experienced |
| Virtual Machines | Management requires direct connections to host; can’t provision new VMs from templates |
| ESX Servers | Management requires direct connections to host |
| Performance & Monitoring Statistics | Historical records will have gaps during outages, still available via ESX Servers |
| VMotion / Storage VMotion | Unavailable |
| VMware DRS | Unavailable |
| vCenter Plug – Ins | Unavailable |
| VMware HA | HA failover works, admission control unavailable |
| VMware View | Cannot provision new desktop instances |
| VMware vCloud Director | Cannot allocate resources or provision VMs |
Why is it important to protect VMware vCenter? vCenter is your single pane of glass into your virtualized infrastructure.
Individual virtual machines and VMware ESX hosts largely unaffected by vCenter downtime, management requires direct connections to ESX Servers
But downtime greatly impacts productivity of VI Administrators
Lets look at the impact of what functionality you would lose if vCenter was not available:
You lose the ability to centralized management
You lose the ability to rapidly deploy new virtual machines
You lose the ability to do performance monitoring within your Virtual Infrastructure
You also lose the ability to seamlessly migrate virtual machines with no transaction or data loss.
And if that was not bad enough you may lose the ability to provide high availability and continuous operations.
And clearly you lose other useful tools such as licence server.
Details
VMware HA is almost independent from the vCenter
VMotion needs coordination of different vCenter agents, thereby requiring vCenter to be operational
Enable Remote Tech Support (SSH)via the DCUI(Direct Console User Interface) August 23, 2011
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Enabling Remote Tech Support (SSH) is ideal production systems, because you can enable it and leave it turned on for an x amount of time, and after the time out SSH is being disabled automatically, so the system is secure again. One small drawback is that you need to have either a physical console access or a iLO, DRAC or some other remote console access.
If you’re running vSphere 4.1 you can also enable this via the vSphere Client, see option two for more details.
Once you have direct console access to the DCUI of the ESXi server you’re able to enable Remote Tech Support (SSH) on the ESXi host, but first you need to login with the right credentials, in most cases this will be the root account.
You will find the Remote Tech Support option under the Troubleshooting Options.
Select Enable Remote Tech Support (SSH) to enable the SSH service, be patient because it will take some time to enable it, if you press Enter twice you will disable Remote Tech Support .
After a few second Remote Tech Support should be enabled, if not press the Enter key one more time until you see a screen as shown above. Sometimes it can be hard to enable it through the DCUI especially when using iLO, but maybe that’s because I’m not patient enough
To enable a timeout on which the SSH service is turned on, select Modify Tech Support Timeout, and hit Enter to continue, this option is not required, it can be useful to provide someone access to the ESXi host for just a few minutes/hours. I recommend you to always set this time out on production systems, because you can’t forget to turn if off again.
Enter any value between 0 (zero) and (one day) 1440 minutes (where zero is to disable it, and 1440 is the maximum) to enable the SSH time out, press Enter to activate it.
To test if it’s working, you can use Putty to connect to the ESXi host.
Once you’re enabled the Remote Tech Support feature you will receive a message within the vSphere Client (both if your directly connected to a ESXi host or through the vCenter Server) indicating that Remote Tech Support Mode is enabled. Personally I like this notification, because it will remind you that SSH is still enabled, so you can’t forget to turn it off
Enable Remote Tech Support (SSH) via the vSphere Client
As mentioned before, with the introduction of vSphere 4.1 you will be able to enable the Remote Tech Support through the vSphere Client, either directly connected to the ESXi host or through the vCenter Server. Bellow I will only describe how to enable it if you’re connected through the vCenter Server. If your doing this by connecting the vSphere Client directly to the ESXi hosts, you can also use these steps because it’s not that different.
If you’re using vSphere 4.1, I recommend using this way to enable SSH for a production ESXi host, because it’s easy to do and it can be done without the need of a direct console connection.
The first step off cource is to open the vSphere Client and logon to you’re vCenter Server, if your not already done that
Once you logged in, select the ESXi host on which you want to enable SSH, and click on the Configuration tab, in the Software screen click on Security Profile. In the Services field click on Properties.
Select the service: Remote Tech Support (SSH) and click on Options.
Click on Start to enable the Remote Tech Support (SSH) service, you can leave the Start-up Policy as it is.
Verify that the Remote Tech Support (SSH) service is running and click on OK.
Once you have enabled the Remote Tech Support Mode you will receive a message on the ESXi host, that the service is enabled.
One (small) drawback of this method is, that it isn’t possible to use a timeout on the SSH service directly within the Services screen, to enable the timeout you need to go to Software/Advanced Settings.
Select: UserVars and enter the required timeout value in the UserVars.TSMTimeOut (note: the timeout is in seconds, in my example I have configured a timeout of 30 minutes –> 1800 seconds) click on OK to enable the timeout feature.
Mubarak Ahamed 