Virtualization Is Not All Roses

An anonymous reader writes "Vendors and magazines are all over virtualization like a rash, like it is the Saviour for IT-kind. Not always, writes analyst Andi Mann in Computerworld." I've found that when it works, it's really cool, but it does add a layer of complexity that wasn't there before. Then again, having a disk image be a 'machine' is amazingly useful sometimes.

Testing PXE terminals

[Anonymous Coward]

I've found that VMware is incredibly useful for testing network booting (PXE) systems. I rolled my own custom Damn Small Linux for PXE booting on our thin client workstations. VMware was great for testing purposes. Everybody loves DSL too, they can listen to streaming audio and MP3s while they work too, since I included mplayer and Flash in Firefox. NX and FreeNX to connect to our terminal server.

Question: Do cards have to support it?

[Anonymous Coward]

Hey I just wanted to know from someone who has tried virtualization, do graphics cards have to support virtualization? I mean I think that the drivers do some initialization when they startup, so will going from one machine to another cause a problem with that? I can think of a situation where one machine has an opengl window open and you go to the other machine to play an FPS, what will happen?

sorry for the AC,
Dan
(interesting that the word in the image is forgive lol)

Virtualization

[DesertBlade]

Good story, but I disagree in some areas.

Bandwidth concerns. You can have more than one NIC installed on the server and have it dedicated to each virtual machine.

Downtime: If you need to do maintance on the host that may be a slight issue, but I hardly ever have to anything to the host. Also if the host is dying, you can shut donw the Virtual machine and copy it to another server (or move the drive) and bring it up fairly quickly. You also have cluster capability with virtualization.

We're about 95% virtualized and never going back!

[Anonymous Coward]

The absolute only place it has not been appropriate are locations requiring high amounts of disk IO. It has been a godsend everywhere else. All of our web servers, application servers, support servers, management servers, blah blah blah. It's all virtual now. Approximately 175 servers are now virtual. The rest are huge SQL Server/Oracle systems.

License controls are fine. All the major players support flexible VM licensing. The only people that bark about change control are those who simply don't understand virtual infrastructure and a good sit-down solved that issue. "Compliance" has not been an issue for us at all. As far as politics are concerned -- if they can't keep up with the future, then they should get out of IT.

FYI: We run VMware ESX on HP hardware (DL585 servers) connected to an EMC Clariion SAN.

Like all technologies, you need a good plan

[caseih]

There's nothing wrong with the technology as such. All of the problems mentioned in the article are not inherent to virtualization, nor are they flaws in the technology. Virtualization just requires some basic planning. What is the average disk utilization (disk bandwidth) of a server you want to virtualize? What about CPU? How about network bandwidth? You need to know this before you start throwing stuff into a VM. VMWare and Xen both allow you to take advantage of multiple hardware NICs in the host, multiple processing units, and also multiple physical disks and buses. Of course running multiple VMs on one host will have to share bandwidth and server throughput. The article is stating the obvious but making it sound like virtualization has an inherent fatal flaw and thus will fall out of favor, which makes the article rather lame.

Same old "doing it half-assed"

[Jagged]

From the article:

Increased uptime requirements arise when enterprises stack multiple workloads onto a single server, making it even more essential to keep the server running.

You don't just move twenty critical servers to one slightly bigger machine. You need to follow the same redundancy rules you should follow with the multiple physical servers.

Unless you are running a test bed or dealing with less critical servers, where you can use old equipment, you get a pair (at least) of nice, beefy enterprise servers with redundant everything and split the VMs among them. And with a nice SAN between them, you can move the VMs between the servers when needed.

Even better if you can, get the servers (or another pair) set up at two sites for disaster recovery.

Yes, this will cost money, but Virtuilzation is not designed to make the bean counters save money. You need a plan to do it right and the budget to pay for all of it.

Re:Yawn

[dthable]

I could also see their use when upgrading or patching machines. Just take a copy of the virtual image and try to execute the upgrade (after testing, of course). If it all goes to hell, just flip the switch back. Then you can take hours trying to figure out what went wrong instead of being under the gun.

Hype Common Sense

[micromuncher]

The article mentions a point of common sense that I fought tooth 'n nail about and lost in the Big Company I'm at now.

For a year I fought against virtualizing our sandbox servers because of resource contention issues. One machine pretending to be many with one NIC and one router. We had a web app that pounded a database... pre virtualization it was zippy. Post virtualization it was unusuable. I explained that even though you can Tune virtualized servers, it happens after the fact, and it becomes a big active management problem to make sure your IT department doesn't load up tons of virtual servers to the point it affects everyone virtualized. They argued, well, you don't have a lot of use (a few users, and not a lot of resource utilization.)

My boss eventually gave in. The client went from zippy workability in an app being developed, to slow piece of crap because of resource contention, and its hard to explain that an IT change forced under the hood was the reason for SLOW, and in UAT, SLOW = BUSTED.

That was a huge nail in the coffin for the project. When the user can't use the app on demand, for whatever reason, and they don't want to hear jack about tuning or saving rack space.

So all you IT managers and people thinking you'll get big bonuses by virtualizing everything... consider this... ONE MACHINE, ONE NETWORK CARD, pretending to be many...

Re:the sad thing is how much we need virtualizatio

[dthable]

And if the software doesn't require a dedicated machine, the IT department wants one. The company I used to work for would buy a new machine for every application component because they didn't want Notes and a homegrown ASP application to conflict with each other. Seemed like a waste of hardware in my opinion.

Re:Yawn

[afidel]

Well, our Oracle servers are DL585's with four dual core cpu's, 32GB of ram, dual HBA's backed by an 112 disk SAN and they regularly max out both HBA's, trying to run that kind of load on a VM just doesn't make sense with the I/O latency and throughput degradation that I've seen with VMWare. I know I'm not the only one as I have seen this advice from a number of top professionals that I know and respect. If you have a lightly loaded SQL server or some AD controllers handling a small number of users then they might be good candidates, but any server that is I/O bound and/or spends a significant percentage of the day busy is probably the lowest priority to try to virtualize. You can probably get 99+% of the benefit of virtualization from the other 80-90% of your servers that are likely good candidates.

Re:Yawn

[herve_masson]

Virtualization good: Webservers, middle tier stuff, etc.

Virtualization *insanely* good: development !

It simply changed my programmer life entirely. How can I keep machines with any flavor and version of the linux boxes I'm working at which can be booted in seconds ? How can I have a (virtual) LAN with dozen machines communicating to each other when developping a failover/balanced service ? How can I multiply the number of machines by a cut'n'paste operation ? I do I rollback a damaging crash or a faulty operation (via snapshots) ? The whole thing even fit in my workstation and works beautifully.

VmWare is the most beautiful and useful piece of software I ever used I think, even with those stupid clock problems when running certain bsd/linux environements.

Jeez, I could not even think of working differently now. For me, this is more than a useful tool; this is a revolutionary tool that makes my job possible, which obvioulsy does not mean it's good and rosy for anything on the planet (who thought it was ?)

I call sockpuppet

[terrahertz]

The article is so brief and so pathetically and obviously assailable on so many points (perhaps all of them), and some of the "comments" on the page really look scripted in advance.

Something's fishy.