Working Centre: Linux User's Group

[da]

Last night was the monthly Linux User's Group. The topic was Xen / Server Virtualization. It was a pretty good high-level overview of the Server Virtualization products. The presenter is a rep for IBM Canada; he knows his stuff, though he really knows mainframes and VMWare, less so, Xen. Apparently they don't have many companies asking about virtual servers, yet; which surprises the heck out of me; I've been hearing of them for over a year now.

I *love* the ideas behind virtualization; such as: replicating a production virtual machine, using that copy as a test-bed, and perhaps spawning that to serve as another test, and discarding the ones you're done with. Disposable computers, hey. 3% overhead for running most services in a virtual system. 0.2 second relocation between hosts (with good bandwith). And moving services from overloaded hosts, if you think ahead and start off with many services on virtual machines on one physical machine.

This isn't quite a mature technology, it's a bit kludgy still. But I've read of some people doing production stuff on Xen, so I know it'll be there soon. My boss may have me working on linux/xen before too long. I hope.

Neat things I learned:

By roughly the end of the year, Intel/AMD VT processor additions will allow virtual machines to call privilaged instructions cleanly, so virtualization won't require modifying the guest's kernel; so, say, Windows can be virtualized in Xen.

It looks like Xen is much faster than Vmware, though I'm suspect of their tests. I believe they were comparing VMWare workstation against Xen, while it's really more like VMWare Server (or VMWare Infrastructure, new product, announced yesterday).

Oh, and I learned you can talk about your organization's NAS (Network Attached Storage) and sound all modern, when really you're using old-skool NFS.

Anyhow, that was my evening yesterday. After the meeting I had some good conversations with Charles and pnijjar, helping them pack up. I even walked off with some books that Charles doesn't necessarily want back.

Comments

[kraig.livejournal.com]

I have some notes on building Xen for Dells on our twiki somewhere, if you want to have a look - not sure how far you've gotten. I'm faffing about building it on my SuSE drive for one of my desktop PCs too - several RTs, look for nugget (the Dell on which I originally built it).

I think it'll be a year or two before Xen is *really* ready for primetime; SuSE/Novell attempt to package it up, but even they say "download the sources and use those instead."

That's not to slam Xen; they appear to be doing a good job of playing catch-up. But they're still the tail in follow the leader, if I may mix two playground metaphors here.

[kraig.livejournal.com]

(and I don't think it's entirely fair to compare speeds of the two systems: VMWare uses a couple of kernel modules, while Xen requires a custom kernel. They've tuned it, hopefully it *will* be faster!)

[da-lj.livejournal.com]

Agreed. Well, sort of. If one wants to run their servers with little overhead, it's totally fair to evaluate them on results. :)

Yeah, a year, at least; but looking at the groups behind it, it's worth watching. He said, watching.

[kraig.livejournal.com]

Yup, no question.

I'm probably biased; I've been using VMWare since 2.0 was Fresh! Hot! New! on my dual-Celery BP6-based system running Linux. At the time, likely RH6 or Mandrake.

But I also Really. Hate. Recompiling. Kernels. That's what turned me off of Linux in the first place, right back to when it used to take 8 hours on my 386DX-25, and on to BSD, who seem to be able to cope Just Fine without requiring it every other week. (One could argue that the BSDs aren't as flexible as a result, but in my old age I'm willing to trade flexibility for stability and a kernel that isn't considered old news at 4 months of age.)