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.

Comments

Yawn

[dreamchaser]

This is the exact same pattern that almost every computing technology follows. First the lemmings all rush to sound smart by touting it's benefits. Soon it is the be all and end all in "everyone's" mind. Then the honeymoon fades and people realise it's a useful tool, and toss it into the chest with all the other useful tools to be used where it makes sense.

Re:Yawn

[vanyel]

Virtualization good: Webservers, middle tier stuff, etc.
Virtualization bad: DBs, memory intensive, CPU intensive.

We're starting to do the same. It looks the articles basically says "managing them is more complex, and you can overload the host". Well duh! They're no harder to manage (or not much) than that many physical machines, but it does make it a lot easier (cheaper!) to create new ones. And you don't virtualize a machine that's already using 50% of a real system. Or even 25%. Most of ours sit at 1% though. Modern processors are way overkill for most things they're being used for.

Re:Yawn

[ergo98]

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.

Indeed, it has become a bit of a unqualified, blanket meme: "Don't put database servers on virtual machines!" we hear. I heard it just yesterday from an outsourced hardware rep for crying out loud (they were trying to display that they "get" virtualization).

Ultimately, however, it's one of those easy bits of "wisdom" that people parrot because it's cheap advice, and it buys some easy credibility.

Unqualified, however, the statement is complete and utter nonsense. It is absolutely meaningless (just because something can superficially get called a "database" says absolutely nothing about what usage it sees, its disk access patterns, CPU and network needs, what it is bound by, etc).

An accurate rule would be "a machine that saturates one of the resources of a given piece of hardware is not a good candidate to be virtualized on that same piece of hardware" (e.g. your aforementioned database server). That really isn't rocket science, and I think it's obvious to everyone. It also doesn't rely upon some meaningless simplification of application roles.

Note that all of the above is speaking more towards the industry generalization, and not towards you. Indeed, you clarified it more specifically later on.

Is this for real?

[Marton]

One of the most uninformative articles ever to hit Slashdot.

"Oh, so now more apps will be competing for that single HW NIC?" Wow. Computerworld, insightful as ever.

why are we reading this garbage?

[philo_enyce]

to sum up tfa: poor planning and execution are the cause of problems.

how about an article that makes some recommendations on how to mitigate the problems they identify with virtualization, or point out some non obvious issues?

philo

excess power

[fermion]

I see virtualization as a means to use the excess cycles in the modern microsprocessors. Like over aggressive GUI and DRM, it creates a need for the ever more expensive and complex processors. I am continuously amazed that while I can run most everything I have on a sub GHZ machine, everyone is clamoring about the need for 3 and 4 GHZ machines. And though my main machine runs at over a GHZ, it still falters at decoding DRM compressed Video, even though a DVD plays fine on my 500 MHZ machine.

But it still is useful. Like terminals hooked up to big mainframes, it may make sense to run multiple virtual machines off a single server, or even have the same OS run for the same user in different spaces on a single machine. We have been heading to this point for a while, and now that we have the power, it makes little sense not to use it.

The next thing I am waiting for are very cheap machines, say $150, with no moving parts, only network drivers, that will link to a remote server.

Virtualization != x86

[HockeyPuck]

Why is it all of a sudden whenever someone says "Virtualization" they imply that it must be Vmware/Xen/windows/x86 platform.

It's not like these issues haven't existed on other platforms. Mainframes, mini's (as400), Unix (aix/solaris/hpux), heck we've had it on non-computer platforms (VLANs anyone...).

And yes using partitions/LPARs on those platforms required *GASP* planning, but in the age of "click once to install DB and build website" aka "Instant gratification" we refuse to do any actual work prior to installing, downloading, deploying...

How about a few articles comparing AIX/HPUX/Solaris partitions to x86 solutions...

Author is completely uninformed

[LodCrappo]

Increased uptime requirements arise when enterprises stack multiple workloads onto a single server, making it even more essential to keep the server running. "The entire environment becomes as critical as the most critical application running on it," Mann explains. "It is also more difficult to schedule downtime for maintenance, because you need to find a window that's acceptable for all workloads, so uptime requirements become much higher."

No, no, no. First of all, in a real enterprise type solution (something this author seems unfamiliar with) the entire environment is redundant. "the" server? You don't run anything on "the" server, you run it on a server and you just move the virtual machine(s) to another server as needed when there is a problem or maintenance is needed. It is actually very easy to deal with hardware failures.. you don't ever have to schedule downtime, you just move the VMs, fix the broken node, and move on. For software maintenance you just snapshot the image, do your updates, and if they don't work out, you're back online in no time.

In a physical server environment, each application runs on a separate box with a dedicated network interface card (NIC), Mann explains. But in a virtual environment, multiple workloads share a single NIC, and possibly one router or switch as well.

Uh... well maybe you would just install more nics? It seems the "expert" quoted in this article has played around with some workstation level product and has no idea how enterprise level solutions actually work.

The only valid point I find in this whole article is the mention of additional training and support costs. These can be significant, but the flexibility and reliability of the virtualized environment is very often well worth the cost.

He must. ESX set up properly avoids most pitfalls

[cbreaker]

Indeed. If you have a proper ESX configuration: At least two hosts, SAN back-end, multiple NIC's, supported hardware - you'll find that almost none of the points are valid.

Teaming, hot-migrations, resource management, and lots of other great tools make modern x86 virtualization really enterprise caliber.

I think that the people that see it as a toy are people that have never used virtualization in the context of a large environment, being used properly with proper hardware. You can virtualize almost any server if you plan properly for it.

In the end, by going virtual you end up actually removing so much complexity from your systems that you'll never know how you did it before. No longer does each server have it's own drivers, quirks, OpenManage/hardware monitor, etc etc. You can create a new VM from a template in 5 minutes, ready to go. You can clone a server in minutes. You can snapshot the disks (and RAM, in ESX3) and you can migrate them to new hardware without bringing them down. You can create scheduled copies of production servers for your test environment. So much more simple then all-hardware.

I'll admit that you shouldn't use virtual servers for everything (yet) but you will eventually be able to run everything virtual, so it's best to get used to it now.

This is FUD

[fyngyrz]

...virtualization's problems can include cost accounting (measurement, allocation, license compliance); human issues (politics, skills, training); vendor support (lack of license flexibility); management complexity; security (new threats and penetrations, lack of controls); and image and license proliferation.

Examine that quote from the article closely. See anything there that indicates virtualization "doesn't work"? No, nor do I. What they are talking about here has nothing to do with how well virtualization works, what they're complaining about is that a particular tool requires competence to use well in various work environments. Well, no one ever said that virtualization would gift brains to some middle level manager, or teach anyone how to use an office suite, or imbue morals and ethics into those who would steal; virtualization lets you run an operating system in a sandbox, sometimes under another operating system entirely. And it does that perfectly well, or in other words, it works very well indeed. I call FUD.