ESX vs. ESXi which is better?

Caution: Articles written for technical not grammatical accuracy, If poor grammar offends you proceed with caution ;-)

So the question is which is better VMware ESX or VMware ESXi. A lot of die hard Linux fans will always say VMware ESX because of there attachment to the service console. The service is a great tool and once upon a time it served it’s purpose. Today there are many other options available to manage your VMware ESX servers without the service console. There is the Remote CLI, the VI ToolKit for Windows (powershell), and last but not least the VIMA.

With these tools you can effectively create scripts to help manage your VMware ESX environment without the service console. The service console opens up an additional security risks for each and every VMware ESX host you have deployed. Mitigating this risk increases the management overhead involved in the maintaining and deployment of these server in your environment. VMware ESX also consumes more server resources than VMware ESXi. The service console in VMware ESX uses CPU cycles and memory that you could be utilizing for virtual machines on VMware ESXi.

As far as feature and functionality VMware ESX and VMware ESXi are equals. They both support all of the Enterprise feature available as part of VI3. There are some add-on products that require the use of VMware ESX such as Lab manager and Stage Manager but hopefully they as well will be ported to VMware ESXi. You can find the VMware ESX and ESXi comparison here.

A growing number of servers are available from all major vendors that have support for embedded VMware ESXi. If you have one of these servers their are even greater benefits to running VMware ESXi. With these their is no need for internal or SAN storage for your boot partitions. Eliminating internal storage is a great way to go green. The average coast of a 73Gb 15K SAS drive is $400.00. Typically you would have (2) for redundancy adding an average of $800.00 to the cost of each server. The estimated annual cost to run a single SAS drive is $23.00 rounded making it $46.00 per server per year. This does no include the additional cooling capacity needed for the heat produce from the drives.

If you have 40 VMware ESX server running in your environment you can save $32,000 in the acquisition of hard disks and $1,840 per year in energy costs, not to mention the benefits to the environment from the reduction in your carbon footprint and well as the reduced maintenance costs. I don’t have any figures on this but there will most definitely a savings in the overall administration effort required to support VMware ESXi vs. VMware ESX. The sheer need to lock done the service console and keep it secured is pretty demanding task.

I regularly hear “We are waiting on VMware ESXi” and when I ask why I never hear a thought out valid answer. I would like to hear your opinion on this topic. Please leave comments as to your views on VMware ESX vs. VMware ESXi I would like to gain some greater insight into why more organizations are not making the switch.

9 Replies to “ESX vs. ESXi which is better?”

  1. The only other argument against ESXi that I have heard is that the internal USB Stick is a single point of failure. But my response to that is that VMware HA will help with this.

    I have also been involved in engagements that have used the ESXi “Installable” version on a boot from SAN configuration. Think about it…You already need the Fibre Channel Adapters, why not carve out a tiny LUN. Usually, the smallest is about 1GB, but then you do not have the internal USB key SPOF.

    Since ESXi doesn’t have any of the extra “fat” of the console OS, there are less security risks involved. Also, I don’t really like what the various management agents do. It always seems that one fix breaks two other things. Each little chunk of extra software exposes a further security risk and uses a few more precious CPU cycles.

  2. Interesting article, I consider the RCLI to be a subset of the VI Perl Toolkit for Linux/Windows and it’s just a set of default utilities that VMware has written and provided to be replacement for the standard esxcfg-* commands. Though, there is much much more you can do with the exposed layer through the VI Perl Toolkit so I guess you would have VI Toolkit for Windows (Powershell), VI Perl Toolkit (Windows/Linux) [RCLI+more] probably makes a little bit more sense else some will take those two as separate products which they’re not since RCLI will not work if the VI Perl Toolkit is not available on either Windows or Linux.

    One thing that came to mind while reading this article, last night I answered a question on the VMTN forum regarding a hung VM. A process was already initiated to try to stop the VM but it continued to run and no new commands were accepted since there is an active process. The solution, use ‘ps’ to find the PID of the VM and killing the PID. With ESXi, this is impossible unless you’re willing to take down the host and reboot, if you’re fortunate to have vCenter/vMotion, move the VM(s). Basically, there is no exposed layer by VMware to forcefully take down a VM if a process is already running. You would have to login to the unsupported busybox console which should only be done when working with VMware support. There are still some limitations that the SC proves useful when you start running into issues and provides an admin to further investigate. With ESXi, you can have the standard logs consolidated through VIMA & vi-logger but if you can’t find the issue there you’re pretty much stuck and require VMware support.

    Also lack of 3rd party agent support on VIMA, I still haven’t seen a single vendor provide an agent. I think APC is the only one that has stated they would work on an agent and the timeframe has shifted and last I heard was end of March… I think many people are still waiting.

    That’s my 2cents, curious to get other views on this.


  3. William has a valid point, no ‘ps’ / ‘kill’ option. This is an argument for some of my customers not use use ESXi at this point in time.

    Another problem people are also currently facing is internal USB keys failing. Although that’s why one has HA it’s not something you should and or would normally take in account.

    Although I really love the concept of a thin hypervisor I also value my service console highly.

  4. You could also eliminate your local storage while keeping a full ESX OS on your hosts by booting your hosts using a san volume. You would need nics that have iscsi initiators on them and configure them correctly, but it would work.

  5. @Dave Convery

    Hi Dave,

    You mention you’ve been deploying ESXi installable with Boot From SAN but this configuration is not officialy supported by VMware. As per the ESXi 4.0 install guide it is “experimental”. ESXi 4.0 embedded on the other end doesn’t suffer from that limitation.

    That is today the single thing that is preventing us from moving towards ESXi…

  6. @Didier Wenger
    You’re correct Didier – ESXi boot from SAN is still only experimentally supported. To update my comment about the USB keys, it seems that HP is dropping the USB key option if favor of SDHC cards. Either way, they are less than $70 (US) and HA can keep the VMs running for you in the unlikely event of a failure.

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