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A client plans to move a database engine to a VM while upgrading to SA12. Currently they use SQLA 9 with 1 processor licence which covers 2 physical processors. The licence model for SQLA 12 is different, each physical processor requiring a separate licence. I googled for hints on that topic and found that page: But that didn't get me very far, there's no such simple case with only one instance or SQLA. The new machine might have 2 or 4 quad core processors (I don't know yet). I'm a newbie when it come's to virtualization (apart from using VM's for test environments). So I'm unable to imagine how to count processors in a VM. |
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As I understand it, the software running in a VM thinks it is running on real hardware. In that sense, if the VM is only presented with 1 processor (whether this comes from 1 of many real physical processors, or merely 1 core of a multi-core processor) it will only be able to see the 1 processor. That is how the software itself would interpret the situation. How Sybase as a company would interpret the licensing is another matter. I am not sure if they license based on actual physical processors on the box housing the VM (which in a large scale VM setup could change at any moment) at that point or again the processors presented to the VM itself. This is all conjecture. Please correct with real Sybase-certified info. |
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I talked to Sybase sales in Germany. To make it short, this is the summary of our conversation :
That sounds logical, if I assume that applications running in a virtual machine can't tell if a processor is "real" or "virtual". |
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This isn't an answer, it's an exhortation: Be prepared to hear your client complain about performance problems after virtualization. Maybe it won't happen, but... if the current non-virtualized database engine uses, say, only a small percentage of the CPU capacity, it may be a good candidate for virtualization... unless it also does a lot of disk I/O and that disk I/O is optimized by heavy use of the RAM cache, and after virtualization the database is starved for RAM, and the hard drive light comes on and stays on 24 by 7.
Caveat Emptor: I have zero personal experience setting up database servers on VMs, and very little second-hand knowledge... 100% of that being tales of woe. My simplistic answer is always "get off", like the simplistic medical advice "if it hurts when you do that, stop doing it." Of course, clients don't often call and tell me when things are going well so perhaps there are many success stories :) 2
We have a few clients using VmWare and one using Microsoft Hyper-something-or-ruther. Our largest client has 2 sharp techs who setup and manage the servers: they buy good hardware, pack it with plenty of RAM and disks, use all the VmWare tools to make servers work great, and the performance is... at LEAST as good as the days when we had excellent, dedicated boxes. Other clients read the marketing white paper, installed VmWare on the same white box they are now using for a single server, and guess what... performance AND EVERYTHING ELSE (like reliability) sucks. 1
Having the sharp techs and the good hardware and the RAM and the disks... doesn't that wipe out the savings that a pile of $300 servers from Tiger Direct would give them? :) With virtualization you have other advantages than just pricing. If you have a hardware failure you can easily bring back the complete system online on a different server. This is also a use case for hardware migrations. So if you want to run your db on a more powerful server you don't have to reinstall everything, you just have to exchange the hardware. Another advantage is delpoyment, you can prestage everything in a VM environment and then you can just ship the VM machine to the productive system. I appreciate every bit of information I can get w.r.t. virtualization. We have some clients using SQLA in a VM and everything runs smoothly (2 x 4 Cores, 24 GB, SAS-SAN ...). This particular client is part of a larger enterprise whose IT department told our client: "you're systems will be virtualized". So it's not about DO IT or DON'T, it's just: how do I count licences if they don't want to licence per seat. |
