VMware ESXi VS Citrix XenServer

Question

We are thinking to get into VDS (Virtual Dedicated Server) business. We want to create instances on our servers and sell it as you may expect. But we couldnot come up with a selection between ESXi and Citrix XenServer.

We want to do this with the veeeeery low money so we are looking as much free tools as we can find. I want advice from you. Do you think it is worth paying money to VMware ?

By the way we will both use linux distros (mainly centos, debian, ubuntu server) and windows.

Additional Info; We were thinking about to host VMs in their own phsycal environment for instance we will buy a server with quad core and 4x500GB raid 5 8 GB of ram and split it into 4 machines and rent it. But also we can go with the shared storage. The thing i loved with Xen is live migration. Because in case of emergancy we can move VMs you know. We also want it to be expandable I mean we may grow our business if we see that it is going good. When we buy 3 new servers we will approx. buy a new licance from VMware and it will cost additional of 300-400$ for each server right ?

Thanks

Answer 1

As free stand-alone products both do a pretty similar job; they work, are fast and quite feature-rich.

What you need to ask yourself is how you wish to manage and automate the work involved in the lifespan of the client VMs, also how many VMs you wish to serve per host server and what your client SLAs will be.

The reason you need to ask yourself these questions is that their answers will define how serious you are about this business and therefore which solution to go for.

For instance neither free product comes with serious management tools or support, you pay for that with either option. In my own experience the management, and especially the automation, tools for VMWare outstrip Xen's so that may be of interest to you if you expect to orchestrate VM creation/deletion. VMWare will also allow you to host more VMs per host server too due to it's use of shared memory. Also VMWare has a more mature set of in-house and third-party tools available to help you automatically measure client SLAs, although as Xen matures it is gaining ground in this area too.

Either way you need to decide how serious you are about this business and invest wisely, I'd advise you invest in some sensible shared storage of some time to allow for live VM migration and/or automatic VM restarts in the event of host server failure.

Getting to your actual question; I'd go with VMWare but mostly because I know it pretty well, although I will caveat that by saying I wouldn't be particularly bothered if I were forced to use Xen (oh and have you considered KVM by the way?)

Good luck.

Answer 2

I have become a bit weary of Xen. I'll explain. Recently, Citrix has released a disaster recovery feature for Hyper-V in their 'Essentials' package. Nothing unexpected with that: Citrix is pretty much in Microsoft's pocket and Hyper-V will probably be everywhere for the simple fact that it comes bundled with Server 2008.

What is unexpected though - at least for me - is that Citrix hasn't as of yet released the same functionality for it's own XenServer product range and will not do so for another 4 or 5 months.

Add that to the fact that the Xen developers have recently failed at several attempts to push the Xen dom0 code into the mainline Linux kernel and Red Hat exclusively pushing KVM in RHEL6 and as a new option in RHEL5, and I would start to wonder which way to go.

With the options you are laying on the table, I'd go for VMware. You might want to consider KVM, like Chopper3 already mentioned. KVM is showing a lot of promise.