When I first heard that Citrix was releasing their flagship bare-metal hypervisor, XenServer for free, I was ecstatic. This is quite obviously a gauntlet being slapped down on VMware’s table, with VMware’s ESXi being released for free just 6 months ago. As a side note, Citrix’s timing was impeccable, as they released the news the day before one of VMware’s biggest user-community conferences,VMwareWorld Europe 2009 .
So, XenServer or ESXi? Check out this table: (disclaimer, from the Citrix site)
| Features included at no cost | Citrix XenServer | VMware ESXi |
| Bare-metal hypervisor | 64-bit | 32-bit |
| Max virtual CPUs | 8 | 4 |
| Windows® and Linux guests |  |
|
| Unlimited servers, VMs, memory |  |
|
| P2V & V2V conversion | |
|
| Shared SAN and NAS storage | |
|
| Centralized multi-server management | |
|
| Resilient distributed management architecture | |
|
| Live motion | |
|
| Shared VM template library | |
|
| Centralized configuration management | |
|
| Virtual infrastructure patch management | |
|
| Intelligent initial VM placement | |
|
| Intelligent server maintenance mode | |
|
| Fine-grained CPU resource controls | |
|
| Hot-swappable disks and NICs | |
I was really hoping to be able to try out XenServer, but my home test box doesn’t have the needed requirements (64bit proc, etc), and I currently don’t have access to any test machines at the organization I serve with. The only machine that comes close to the requirements is my personal laptop that is already dual-booting Ubuntu and Vista. So I thought I would try to install it on external usb media.
The best exertnal media I could come up with was a old ide 2.5″,40GB hard drive I had pulled out of a laptop recently. So, using a ide-2-usb adapter, I booted up the XenServer installer, making sure to select the external hard drive to install to.
After the reboot, expecting for the external drive to boot, I see XenServer starting to load, then a kernel panic, and a reboot. Well, after watching this process for a minute, I was able to discover that the kernel was panicing because of something to to do with booting from a usb device.
After doing a bit of googleing, I was able to find this guide, that helped me enable usb support in intird to allow usb booting. (I did have to tweak the instructions a bit, since I was installing 5, and not 4.1)
After working this black magic, I got XenServer to boot on my laptop. After installing the Xen client on another laptop, I was able to admin the server.
I really like it!
The biggest feature for me, and why I will be using it over ESXi, is that Citrix made the VM manager, XenCenter, free, instead of charging for it, like Vmware is doing with VMware Infrastructure 3.
I’m sure I will be blogging more about it, but I thought I would just post about the educational install! :)
Edit (05/09): As requested in a comment: To tweak the enabling usb support in initrd for 5.0 U3, I just had to use the updated filename for the primary initrd image file, instead of the quoted primary initrd image file, since it was for 4.1.
Josh
Defensive Depth 
Hi
I am running esxi free version on our production servers. We are a small shop but got a fair share of servers. I was reading through citrix making theirs free and seeing whats offered and was blown. But seeing you had been playing with both was wondering if there is anything that you find in esxi that you would like to have seen in citrix or missing or something.
Love the article.
Thanks
Aben
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Hi there,
I would really appreciate it if you would let us know how you tweaked the install for Xenserver 5 – I am not that hot at Linux but tried to follow the guide for 4.1 to install 5.0, but had all sort of issues with the boot image part.
Thanks,
JG
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I’d like to know what laptop you installed Xen Server on? Would it recognise the onboard sata?
Apparantly the Dell Latitude D630 works!
I’m thinking of installing onto a laptop so it doubles up as an UPS.
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Hi mike–
I installed it on my Dell XPS M1330.
Good luck!
-Josh
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The Question I have is did you get the message about your hardware not supporting Hardware Virtualization. I am using a HP 6710B with Intel Duo Core T7100 CPU with 4GB’s of RAM.. Enabled the Virtualization Technology in the BIOS but I am still getting the message. Haven’t tried to create any Windows VM’s yet. Also did you install the Linux Pack?
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@ Derrick:
Have you done a cold boot since enabling the vt in the bio? See http://forums13.itrc.hp.com/service/forums/bizsupport/questionanswer.do?admit=109447627+1262093860493+28353475&threadId=1362005 for more details.
And yes, I did install the Linux Pack.
Good Luck!
-Josh
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@Admin
I didn’t do a cold boot so that might be the issue, I will try that. Is the Intel-VT option so you can run 64bit Windows OS because I remember running VMware ESX on HP G3 and G4 servers that didn’t support Intel-VT. It just seems that all the Hypervisors are requiring Intel-VT lately.
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