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Can you help me with my software licensing question?

We are currently evaluating two free bare-metal virtualization product: VMware ESXi 4.0 and Citrix XenServer 5.5. While both look good on the reviews, we are curious about their licensing.

A quick glance at XenServer Installation Guide (published June 2009), I found that we have to acquire free license on annual basis. This raises a concern, what will happen if Citrix decide to stop releasing license.

Quoting from the document:

Q: The XenServer license has expired. What is going to happen?

A: If the license on a XenServer host expires or goes beyond its activation date while the system is still running, all active virtual machines continue to run as long as the host system is not disrupted. However, new VMs cannot be launched. If the host system is then disrupted (through a power failure, system restart, and so on), a Citrix Essentials for XenServer system will reverts to Citrix XenServer-level functionality when its host is restarted.

Do you think we should continue evaluating XenServer, or drop it in favor of ESXi?

EDIT: We tested further by setting the system clock on the host one year ahead. After that, we cannot boot all the VMs. So it's not Essentials license that expired, but the XenServer itself.

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marked as duplicate by Skyhawk, Shane Madden, Ward, Scott Pack, mailq Nov 7 '11 at 16:03

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

up vote 2 down vote accepted

A Citrix employee has stated:

Yes, it does have to be renewed every twelve months. Citrix commits that it will either make renewal available or, if we ever chose to end the renewal system, will deliver permanent keys.

Like Geoff says - if you're taking anything from a vendor for free, then they're under no contract to supply features or services to you and the landscape may change in the future. The same in some sense applies also to OSS.

Nevertheless it's highly unlikely that Citrix would reverse their decision. Just as it's unlikely that VMware might stop issuing free perpetual ESXi licenses. Continue evaluating the product and it's alternatives to assess strengths and weaknesses all over.

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"Citrix Essentials for XenServer system will reverts to Citrix XenServer-level functionality when its host is restarted."

Except that "Citrix Essentials" is the for-pay component.

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+1 this, it's important. I can't find any documentation that suggests what happens after the dissolution of the old Express/Enterprise split. – Dan Carley Jul 6 '09 at 9:27
I got an impression that the documentation is not up to date, even the title say it's for XenServer 5.5.0. – Arie K Jul 6 '09 at 9:44
After re-reading it the wording does actually make sense. The last part applies only to those using Essentials licenses. The rest applies to everyone. – Dan Carley Jul 6 '09 at 10:01

I used XenServer 5.5 since their initial release and it sucks big time. The gui is buggy, the servers lock when you change some configs and iSCSI is slow. To save you some time: Go to their forum and search for snapshot problems, iscsi performance and driver compilation. Their kernel version is 2.6.18-128.1.6. I feel much better running open source Xen and follow Red Hat's patches. Props to Mark Pace who wrote this: I migrated all my servers back to CentOS 5.4 + open source Xen and I couldnt be happier. I wish I never did the transition from Xen to XenServer and waste my time and make me look bad.

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I had problems with PV drivers for OSS Xen for Windows while the Citrix drivers worked like a charm. – Hubert Kario Oct 31 '10 at 19:18

It's called vendor lock in. VMWare are just as likely to change their licensing on a whim as Citrix are. Licensing is for the benefit of the vendor and always to the detriment of the user.

You need to factor the chance of an about turn in the licensing by citrix, with cost, feature set, stability, performance and management tools to get to a decision of which way you'll go. Personally I think in the long term the choice will by hyper-v if you come from the windows world (and therefore are happy to accept restrictive licensing and vendor lock in), or KVM if you're from the linux world.

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Primary difference in this case is VMware doesn't require us to obtain license every year, nor "halt" the system if the license expires. – Arie K Jul 6 '09 at 9:41
Getting a new license each year is the difference. I don't believe there is any requirement to halt the xen server if your license runs out, it just prevents you from (re)starting guests. It's an odd licensing requirement. I suspect it's done for a couple of reasons. Keeping track of the install base. Forcing people to upgrade by not issuing a new license to someone running an old release. – goo Jul 6 '09 at 10:09

I've got 4 XenServer boxes running with 16 VMs, and a FreeNAS box for iSCSI/shared storage.

Not so much as a hiccup since install. The license was for Essentials (trial) at first, and when that was close to expiring, I went online and got a new free license (just in case). Had it in minutes, not days.

Anyway, applied the new license file, and all kept on going. Have taken one box offline to replace motherboard (more SPEED!) and did a reinstall of that box just to see what would happen. Installed with the same license, and all is well.

Even applied the lastest XenServer update and thing kept on going.

The very existence of my VMWare systems are at risk I ponder moving all of them over to XenServer. Free live motion is a big deal to me, so....

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We don't have any of those issues. We are running 75 host with XenServer 5.5 hosting our virtualized citrix Xenapp environment and have no issues with licensing or slow performance. I have seen some bugs with the GUI but nothing to terribly inconvenient. yearly renewal of Licensing while a pain is not bad and we have nopt seen any of this 3 month stuff the person above is claiming. I have not used iSCSI with it so no comment there.

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