SageTV server from a HyperV VM?

[Fuzzy]

Originally Posted by stanger89

The question is what does consolidating with VM's provide/offer that simply consolidating into a single machine doesn't?

Ie what's better about running multiple VMs vs running just multiple apps? For example I've got Sage, IIS (for cacti), J River Media Center running on my "server", but I just run them as apps. What would running them in VM's gain me?

Thank you Stanger.. that's what I was trying to ask...

[gplasky]

Virtual machines are better at multitasking (so to speak-if you think of each virtual as running a task. If task=application) than multiple applications running on a single OS. If the application is explicty written for use multiple threads/cores/processors then it may work well on a single OS. Most aren't written that well. But it is easier to set one app up on individual VMs and allow the Host machine to manage all the memory and CPU/threads/cores/processors no matter how well it is written to take advantage of CPU/threads/cores/processors.

One primary difference between the two server consolidation methods is that virtualization is a server-level technology while multiple applications is an OS-level technology. Virtualization enables much more granularity because each virtual machine (VM) requires its own OS and thus can be specifically tuned to run that single application.

A single machine with a multiple port NIC can actually take advatage of those multiple ports dynamically. In VMware you can actually create virtual switches that you can build on demand at run-time to provide different functions, including: Layer 2 forwarding, VLAN tagging, stripping and filtering. Layer 2 security, checksum and segmentation offloading.

I'm just throwing some features out there for an example. Imagine a virtual Sage server configured to team 4 NIC ports on demand when required (like recording) and your J River server playing your music over your LAN via the NIC port on your mb and neither one is affected performance-wise from the other. All the OS settings on your Sage Virtual server is optimized for just that-no compromises. Same for your J River VM.

The other thing is a misbehaved app on a virtual server will not bring done the machine, just the virtual. So if there is a memory leak occuring for an app it will only affect the memory allocated for that VM and not the memory for the entire server.

Now in your most common home networks virtualization is overkill. But if you are of the technology-inclined there is a lot of tuning tweaking that can be accomplished. And advantages. There is also disadvantages. Virtual or not you are now managing multiple servers/machines. And then there is backup. But virtual technology also has some solutions for that also.

Gerry

[Fuzzy]

I think most of what you discussed gerry can be done just as well in the host OS (QoS controls for the network cards, etc)... the only point I'm buying is the misbehaving application only messing up it's own VM... I'd prefer not to run said applications.. ;-)

[gplasky]

Originally Posted by Fuzzy

I think most of what you discussed gerry can be done just as well in the host OS (QoS controls for the network cards, etc)

For the most part-true. But as in my example how would you dedicated a single NIC card to be used by only a single application on your single server\OS? You have many more options in a VM and options are good.

Originally Posted by Fuzzy

the only point I'm buying is the misbehaving application only messing up it's own VM... I'd prefer not to run said applications.. ;-)

And so now you have a VM created the same as your production VM which allows you ease of testing for those misbehaved apps. And in a VM the hardware is all seen to be the same in each and every VM. You don't need physical machines which may have different hardware that could test differently.

I'm just saying there's more to it than meets the eye.

Gerry

[aflat]

For you tinkerers VM's also give you the ability to clone a VM. So you can have Sage running perfectly well, clone it, pause it, start your clone, and tinker. Then bring your original VM up and you didn't break/change anything until you are ready. Or take a snapshot before you upgrade, then upgrade. If it didn't work, revert to the snapshot, in 30 seconds your back to a working state.

I use them all the time, Sage doesn't run in one, because I use firewire to tune, but that's about the only reason.

[stanger89]

Originally Posted by gplasky

Virtual machines are better at multitasking (so to speak-if you think of each virtual as running a task. If task=application) than multiple applications running on a single OS. If the application is explicty written for use multiple threads/cores/processors then it may work well on a single OS. Most aren't written that well. But it is easier to set one app up on individual VMs and allow the Host machine to manage all the memory and CPU/threads/cores/processors no matter how well it is written to take advantage of CPU/threads/cores/processors.

One primary difference between the two server consolidation methods is that virtualization is a server-level technology while multiple applications is an OS-level technology. Virtualization enables much more granularity because each virtual machine (VM) requires its own OS and thus can be specifically tuned to run that single application.

First, I do understand a bit about how VMs can be beneficial. I work with a real time system that uses VMs at work. But there's a big difference from what I can tell between that and say VMware. At work, our VM system is setup to forcibly limit each VM to a certain amount of CPU time. It allow the VM CPU for a certain percentage of the cycle, then moves on to the next VM, and so on. Each app is tuned so that it always completes it's processing in the time allotted. There are several benefits to this, one if you're building an app, you know no other app can squash you and steal CPU time. And second, since all apps are built to run in the time allotted, that guarantees that everything runs on time, without interruption (frankly I think media PCs would benefit hugely from this architecture, but I digress).

From what I can tell (Playing with VMware server) there's no such option. You can tweak the priority of each VM, but you can't limit a VM to say 42% of CPU time.

OK, I guess EXSi does have that.... But...

A single machine with a multiple port NIC can actually take advatage of those multiple ports dynamically. In VMware you can actually create virtual switches that you can build on demand at run-time to provide different functions, including: Layer 2 forwarding, VLAN tagging, stripping and filtering. Layer 2 security, checksum and segmentation offloading.

I'm just throwing some features out there for an example. Imagine a virtual Sage server configured to team 4 NIC ports on demand when required (like recording) and your J River server playing your music over your LAN via the NIC port on your mb and neither one is affected performance-wise from the other. All the OS settings on your Sage Virtual server is optimized for just that-no compromises. Same for your J River VM.

I'm having trouble seeing how that's really beneficial, I mean in real world circumstances, eg our reality where a single Gig-E link is plenty for all of the above.

Which is really what I'm getting at, those of you "keen" on Virtualizing your home servers, have you tried it both ways and achieved better results virtualizing? What was better? How much better?

[src666]

Virtualization, like any technology, can have both positive and negative effects. For me, the positives include:

Isolation - By isolating the host operating systems, problems on one don't affect the others. I can patch/update/take down any VM systems and processes I need to without affecting other critical operations.

Versioning - It's a lot easier to build a secure web server if it doesn't have to run any other processes. It's a lot easier to manage software that is picky about it's environment if you don't have to update the environment to support other applications. I also run side-by-side Linux and Windows instances for different tasks.

Hardware overhead - Goes with the first two. If I had to run things on different systems to keep things isolated/versioned correctly, then I would need more hardware, more power, more space, more effort maintaining everything.

Just to clarify, I'm combining as much as possible/reasonable into a VM environment. I'm not moving my Sage server to that environment, because I have a mix of PCI and HD Homerun tuners that wouldn't be supported. But let's not start bashing other's choices to do so. There are good and reasonable reasons for such a move, even if they don't apply for everyone.

[src666]

Originally Posted by stanger89

First, I do understand a bit about how VMs can be beneficial. I work with a real time system that uses VMs at work. But there's a big difference from what I can tell between that and say VMware. At work, our VM system is setup to forcibly limit each VM to a certain amount of CPU time. It allow the VM CPU for a certain percentage of the cycle, then moves on to the next VM, and so on. Each app is tuned so that it always completes it's processing in the time allotted. There are several benefits to this, one if you're building an app, you know no other app can squash you and steal CPU time. And second, since all apps are built to run in the time allotted, that guarantees that everything runs on time, without interruption (frankly I think media PCs would benefit hugely from this architecture, but I digress).

The point isn't really to allocate overall CPU time as one big bucket. You can assign VM's to _specific_ processors, or even multiple processors (VM1 gets core, VM2 gets cores 3&4). The price differential between building a box with a dual core CPU and 2 gigs of RAM vs. a quad core with 8 gigs is minuscule. It's absolutely a LOT smaller than building 2 boxes, or 3. So if you can put 2 or 3 boxes worth of work onto a single system, the cost savings can be substantial. My prior post outlines some of the reasons for not just putting everything under a single OS install on that box.

[stanger89]

Yeah, I'm just not seeing how those reasons impact a home/Sage server.

[hufnagel]

as more features and services are brought into home computing sphere it can be very beneficial to be able to "sandbox" those features and services into seperate machines, either as physical or virtual. the nice thing about virtual is it makes it VERY easy to backup, restore and "practice" changes without potentially ruining a running system as others have said.

oh and another interesting aspect. once a machine is "virtual" it doesn't really care what kind of machine it runs on. so you could perform a major hardware upgrade that normally would result in you reinstalling the system from scratch without having to do anything that substantial. at worst you will need to reinstall the HOST environment (ESXi, Hyper-V, etc.) but you could then just migrate the VM images over to the new hardware with minimal downtime. no major driver changes, no hardware image problems, etc.

[src666]

Originally Posted by stanger89

Yeah, I'm just not seeing how those reasons impact a home/Sage server.

Then you need to think beyond the simple "this is a SageTV server" to the whole computing environment. My house isn't built around Sage, even though Sage is a major feature. I use the solutions that are best for my environment.

This isn't a SageTV issue. This is an option for people to use, and it can work with SageTV under the right circumstances.

[DigitalMan]

I've used virtualization while doing development work for years and years, but was never a fan of virtualization. Most of the types of apps I run on my own servers are generally things I never would have considered virtualizing.

But then we got some servers at work with 5500s in them and it quickly became obvious these things seem to run VMs at native speed. All the systems I've used in the past had virtualization overhead I wasn't willing to accept in exchange for the management benefits.

Of course having a 35% sale pop up 2 weeks later made it an easy decision. I had been pondering how to replace my aging servers and here suddenly all my sticking points were gone.

Having 30 days to prove it would work properly or get returned also helps. The WAF is important to a happy household, but I have my own expectations that I'm not going to put aside.