This message shouldn't really go in this forum as it's a question about which is the bext hypervisor for me to use - Hyper-V, ESXi or XenServer Express. But there isn't a forum that's not hypervisor specific so here it is. Hopefully I won't get a Hyper-V "biased" answer from posting in this forum!
I currently have a small office LAN and am running a linux server which provides many services: IMAP, firewall and internet gateway (Shorewall), file shares (Samba), web filtering (Dansguardian), DNS, DHCP, MySQL, mail filtering (Spamassassin), mail fetching (Fetchmail) etc. It's running on old hardware with 2 NICs - one connected to an ADSL2+ modem and the other connected to my internal LAN switch.
One concern I have is that if the box gets compromised or something goes wrong with it, then ALL these important services are put at risk. So my plan has always been to split out the internet functions onto a low spec separate box which will essentially just run some sort of Shorewall installation, and everything else will be on a separate box hived off from the internet. I've just bought a new PC for the job and I'm going to do this by achieving this setup via virtualised servers.
My question is whether I should use Hyper-V, VMware or XenServer as the hypervisor. As it's a small office LAN I'm not going to have clustered servers etc, so the criteria will be around support for guest OS's, virtual machine management tools, ease of use. I'm also thinking I might set up a few virtual PCs for testing purposes (my wife's a web designer so it's good to have different PCs running different OS's/browsers for testing purposes). Also, it would be good to be able to take snapshots for backups.
Great question and welcome to the world of virtualization! You've hit the nail on the head by realizing that your "eggs in one basket" approach is a tough place to be if one of the services happens to clobber the others. In your case, unless you're ok adding a Windows-type system to your current Linux-only environment, ESXi is a better choice. If, however, you're ok with adding Microsoft software to your environment, Hyper-V is a good choice.
However, given your penchant for Linux-based services, I'd highly recommend that you go the ESXi route rather than Hyper-V. Both are free but ESXi provides broader support for different Linux variants. Here's a link to VMware's guest OS installation guide (http://www.vmware.com/pdf/GuestOS_guide.pdf), which provides detailed information for getting ESXi to play nice with a whole ton of Linux variants.
Further, from a density standpoint, you're likely to be able to support more virtual machines on the ESXi box since the virtualization software itself has a much smaller footprint than Hyper-V.
One drawback to ESXi - VMware's host hardware support requirements are quite a bit stricter than Microsoft's for Hyper-V. Even though it might work, you probably won't be buying a knock-off server and expecting perfect support under ESXi. With Hyper-V, you can generally get drivers pretty easily and run on a broader range of hardware. If you go the ESXi route, I'd recommend that you get a new server, too. Dell has some REALLY good server deals at their outlet store: http://www.delloutlet.com.
From Wikipedia: A hypervisor, also called virtual machine monitor (VMM), allows multiple operating systems to run concurrently on a host computer — a feature called hardware virtualization. The hypervisor presents the guest operating systems with a virtual platform and monitors the execution of the guest operating systems. In that way, multiple operating systems, including multiple instances of the same operating system, can share hardware resources.
In short, a hypervisor allows one to run multiple instances of virtual machines on a single hardware platform, enabling better overall utilization of the resources.
ORIGINAL: Scott Lowe I'd love to hear back on what you decide to do! Scott
There weren't many responses ot this one. I've done a little trial and error and would like to share my findings so that it may help others with a similar question.
XenServer 5.6 Express Edition Cons: No way of converting physical CentOS server to XenSevrer 5.6 VM - have to reboot physical box with XenServer CD to copy P2V and this has to be with XenServer 5.5, not 5.6 (as support for it stopped in 5.6 for some reason). Linux VM templates exist for CentOS, RHEL, Oracle and SUSE – but not Ubuntu which is surely one of the most popular distros out there.
Pros: Free. Can take snapshots. Can organise VMs by conceptual “folders”. Clipboard sharing between VMs. Hosts can be powered on/off from XenCenter. XenServer tools for Win/Linux improve disk and network performance. XenCenter user interface quite good. Small download (~450MB)
Hyper-V Cons: Large download (~1.5GB). Requires a lot of management eg turning off firewall, downloading updates before you can get properly started. Lots of security updates to download & install – this could become a constant PITA. Supported guests seems to be Windows only according to http://support.microsoft.com/kb/954958. Can't import a physical linux server - need Platespin to convert physical linux server to virtual and this isn’t free. Installing Remote Server Administration Tools is a PITA. And it needs Vista or Win7 – XP not supported. When Hyper-V Manager got up and running I got a message saying “You do not have the required permission to complete this task” – had to create a new account on hypervisor Hyper-V to match my Win7 client account. Then I got a message that RPC connection couldn’t be established which was fixed by temporarily turning off my Win7 Norton Internet Security firewall. At this point it became clear it was time to give up and move on - life's too short.
Pros: Free. Can take snaphots (though I think it requires the use of Volume Shadow Services somehow). I'm not trying to bag Microsoft here, but getting Hyper-V was a painful exercise and while I'm sure it's a fantastic product with the full weight and expertise of Microsoft behind it, I just found it too tortuous to get anything done and got tired of tripping over all the gotchas. I'm sure as the product develops things will get easier, but at the moment it really felt like pushing stuff uphill.
ESXi 4 Cons: Notoriously picky about hardware (though was OK on mine with Broadcomm & Intel NICs as I had done some research beforehand). This is probably the biggest gotcha for people who just want to try things out. Also, v4 only works on 64 bit hardware - try v3.5 if you have 32 bit hardware.
Pros: Free. Small download (~400MB). Very quick & easy installation. Small server foorprint. Support for pre-built VMware appliances. Standalone Converter Client is great and it converted my physical linux server in 48 mins without issue - cloned server came up perfectly 1st boot. vSphere client management interface is very functional. Support for snapshots. 3rd party add-on product support seems quite rich (eg tools and utilities for backing up virtual machines etc).
Conclusion For me, ESXi was a clear winner. It was small to download, REALLY quick to install, and has great support for a wide range of guest operating systems. And the real clincher was the Standalone Converter Client (also free) which did a great job at converting my physical linux server to a virtual machine. If XenServer had such good P2V support it could have been a contender too - but it doesn't. Its only issue is hardware support, but if you do some homework up front to ensure your hardware will support ESXi then I think this is the best option.
< Message edited by philled -- 16.May2013 6:05:29 AM >