Can ESXi (or ESX) co-exist with other OS?

[xhawk2010]

My PC server has windows 2008 installed right now.

And I want to try ESXi (or ESX), but I still want to use windows 2008 some time (not in VM).

Can ESXi (or ESX) co-exist with other OS? just like GRUB bootloader of redhat linux can?

By the way, which is better, ESXi or ESX?

[AWo · Accepted solution]

My PC server has windows 2008 installed right now.

And I want to try ESXi (or ESX), but I still want to use windows 2008 some time (not in VM).

No, ESX(i) is a bare metal hypervisor. It cannot co-exist with an other OS on the same hardware.

Can ESXi (or ESX) co-exist with other OS? just like GRUB bootloader of redhat linux can?

That may be possible. I guess that is something the bootloader must figure out.

By the way, which is better, ESXi or ESX?

IMHO that is the wrong question. In general both have the same kernel, so they offer you pretty much the same. But ESX(i) lacks a console and the free version can also not be integrated into vCenter without buying the appropriate license.

But regarding virtualisation, performance and reliance they are the same.

AWo

VCP 3 & 4

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[DSTAVERT]

Two possibilities. If your server has support for hardware virtualization you can use VMware workstation 7 and install ESX(i) as a guest OS and test to your hearts content. With enough RAM and CPU you can install more than one copy of ESX(i) and test the advanced features like HA and vMotion using the Windows server as a shared storage server.

Second way to test would be to disconnect the internal drives (VERY IMPORTANT) and install ESXi to a USB stick. You would need to either add a new drive or use a network storage device (iSCSI or NFS) for a datastore but you can switch back just by reconnecting the drives and removing the USB stick.

[golddiggie]

Second way to test would be to disconnect the internal drives (VERY IMPORTANT) and install ESXi to a USB stick. You would need to either add a new drive or use a network storage device (iSCSI or NFS) for a datastore but you can switch back just by reconnecting the drives and removing the USB stick.

Not completely accurate...

For one thing, as long as the bios of the system supports booting from USB devices (more especially flash drives) then you can boot from the ESXi install disc, target the thumb drive, and install directly onto that. Valid instructions can be found here... Use the "Install ESXi to a USB device direct from the install CD." set. I've done this already, with a system that had an OS already installed on the local drives, leaving those connected the entire time. No issue at all booting from the ESXi flash drive on that system, or on others in fact.

You will want either a fresh drive inside the system you'll be using as a 'part time' ESXi host that can be formatted for use with ESXi, or an iSCSI target that you can connect to (or NFS if you want to be limited). You can run SAN emulation software on another system, with sufficient storage, to do that. Software such as StarWind could do the job for you (with a single host). Just don't expect stellar performance out of it.

Personally, I don't like the nested ESX/ESXi method within VMware Workstation. I know, it's officially supported now, but there are limiting factors for what you can use it with. You won't be able to install any 64 bit operating systems, so Server 2008 R2 is out (or any x64 Windows operating systems). You will also have issues if you want to migrate between a physical host and the nested host (it requires additional configurations/settings in order for the VM's to migrate between them).

In my opinion, get a system to run ESX/ESXi 4 and let it do just that. Don't Mickey Mouse things trying to use two OS's on the same physical box, booting between them. Dual/multi-booting is a legacy item (also in my opinion) that's a hang-over from the 1980's/1990's... It no longer has a valid place in todays environments. I've seen many systems on sites such as Dell's outlet store where you can get a system that will run ESX/ESXi just fine for under $1500 (some even less). If you set up an iSCSI SAN (either hardware/true SAN or via software) then you don't need much for storage on the host. A mirrored pair of fast drives (hardware RAID) will do the trick (as small as you can get these days, or over 20GB). I'm even looking to get a pair of 30GB SSD's for my next host server(s) that I'll be bringing online. Those drives are very cheap these days, and the performance will be more than enough. I might just use a single, having the second as a spare, and use host profiles to ensure my configuration can be restored in the even of a drive failure. I will be getting the iSCSI SAN soon, where all my VM's will reside (either RAID 10 or 50 with 12-16 SATA spindles, leaning more towards the 16). Yes, this is no small investment, overall, but when completed, the environment will be able to handle everything I throw at it, and more. It will also be online for the next 4-6 years, so spread out over that time line, it's a small investment.

I believe that I have about $2000 invested in my current ESXi host server (Dell workstation T7400 with two 146GB SAS drives to boot from, a pair of 7200rpm 1TB SAS drives as the datastore, 16GB RAM). I'm starting to need more RAM with 8 VM's running, with a couple of them being Server 2008 editions. It's been doing just fine until I start piling those OS's onto it... Now I'm at ~75% memory usage, which needs to be addressed before I spin up any additional 2008 VM's. I can get away with some lesser demanding VM's for now, but that's about it...

Network Administrator

VMware VCP4

Consider awarding points for "helpful" and/or "correct" answers.

[DSTAVERT]

Second way to test would be to disconnect the internal drives (VERY IMPORTANT) and install ESXi to a USB stick. You would need to either add a new drive or use a network storage device (iSCSI or NFS) for a datastore but you can switch back just by reconnecting the drives and removing the USB stick.

Not completely accurate...

For one thing, as long as the bios of the system supports booting from USB devices (more especially flash drives) then you can boot from the ESXi install disc, target the thumb drive, and install directly onto that. Valid instructions can be found here... Use the "Install ESXi to a USB device direct from the install CD." set. I've done this already, with a system that had an OS already installed on the local drives, leaving those connected the entire time. No issue at all booting from the ESXi flash drive on that system, or on others in fact.

I understand that the drives can be left in place. How would you explain things if for some reason ESXi grabbed the disks as a datastore and the poster ended up loosing their Windows data. You may have ESXi experience but the poster does not. It doesn't take much to destroy data sometimes no matter how careful you are. Err on the side of safety especially with new users.

[xhawk2010]

Thanks for everyone for giving me detailed info.

For the first question, someone else told me they might co-exist on different hard drives,

just like DSTAVERT's suggestion to use a USB stick.So the bootloader might be hacked to work this out.

For the second question, for my understanding, ESXi is a bare metal hypervisor, while ESX has hypervisor

embedded in a Linux OS.(Is this right?); so, without OS overhead, ESXi might have better performance, but

have few features than ESX.

I forgot to say I'm just using lab machines for testing, not for production. But golddiggie's advice is so valuable for practical implementation.

[golddiggie]

ESX and ESXi are virtually (no pun intended) identical EXCEPT that ESXi doesn't have the service console on top of the hypervisor. Thus ESXi has a smaller footprint, is more secure, has less patches that need to be applied, etc. These are all reasons why a future release of ESX will go away and we will be left with ESXi.

As for the hardware I listed... That is my lab configuration, not production. For production, I would go with better storage (EqualLogic iSCSI SAN, or whatever brand you prefer, with the performance level needed for your environment), at least three servers (we're getting three R710's at work to take over for five older HP servers) and redundant network switches. For production environments, you need redundancy (no single point of failure) from enough NIC ports to be redundant, to dual switches (or parts of existing switches), to dual controllers on the SAN (both drive/RAID and network). Not building in the redundancy from the start leaves you vulnerable to those single points of failure. I don't know of many (or even any) companies that would be willing to have their server infrastructure down due to a single point failure.

I am building up my lab to resemble a more production level environment. This is so that I can more accurately test items in the lab before making any recommendations at work. I prefer to have my lab not on company property so that there's absolutely zero risk of any leakage into the production environment. Plus, when it's at home, I can have ready access at all times (even from work).

I find that the longer you work on a lab, the more demand you place on it for testing, or R&D, the more it starts to resemble a production environment. I'm sure that by some standards, my lab is a production level set. For me, it's not (well, not yet). Until I can lose half of the physical hardware and still have everything (or designated VM's) up and running it won't be production worthy. Of course, I DO have UPS units connected to every aspect of the environment (one dedicated to the host). All ports are both surge and battery backup, 1500VA each. Anything that comes anywhere near the environment is placed on one of the UPS's (I have three currently, when I get more hardware, I'll add more as needed).

Something else to keep in mind... Booting from the USB flash drive for ESXi is not the same as old school dual/multi-booting. I wouldn't recommend 'hacking' what's on the flash drive to place it onto a physical drive. With ESX/ESXi being as efficient as it is, there's really no reason to multi-boot. Make the main OS ESX/ESXi (whichever you settle on) and then make the Windows 2008 a VM. You will need another system to install the vSphere Client onto in order to administrate the ESX/ESXi host (including setting up the VM's), but that's the same either way. I wouldn't even contemplate trying to dual boot my ESX host with any other OS.

Network Administrator

VMware VCP4

Consider awarding points for "helpful" and/or "correct" answers.