Should I virtualize?

[Jawloms]

Hi all,

 

I've been looking around at this, but would like your input too. I support a primary who has a six year old server running 2003R2 which they are replacing. The new server will have two 128GB SSDs, two 1TB Veliciraptor 10K drives and 8GB of RAM (This is decided and isn't changeable). Should I install Hyper-V and then make a virtual DC and a virtual file server on it (obviously with room for more VMs and the ability in future to move VMs if needed), or just make it a physical DC with network shares on it. I am well aware I don't make it a physical DC and put Hyper-V on.

 

Thank you for your opinions.

 

Stuart

[Domino]

how much storage are they expecting to get out of it? I suppose two RAID1 groups with boot drives on the SSDs and data on the Large drives would be doable. Probably preferable to the file shares on a DC.

 

However I'd be concerned about the expectations for the hardware given the limited resources

[snagrat]

Depends on size of school.

 

You could virtual a DC and File server as one server rather than two. You could allocate up to 6GB to that machine then

[Jawloms]

The school has about 150 kids, 50 computers and a dozen laptops. They are currently using around 200GB of data.

@snagrat - Why virtualise that instead of doing it physically? I'm not challenging your suggestion, I just want to understand it.

[snagrat]

No reason really.

 

Doing it virtual means if you ever wanted to shift if to new hardware you could very easily, whereas a physical machine would need fully migrating.

[tmcd35]

What do you hope to gain from virtualisation? What other roles does the server provide? In all honesty I'd probably go for a single multi-role physical server in this instance, unless there is a compelling reason otherwise?

[Sephiroth]

I would be very wary of having a single dc that is virtual. I had that for a while when I was setting my network up. The VMs don't keep time very well, so a server that relies on perfect timing for authentication is not advisable as a VM.

 

If you can get another server for a primary DC (anything that runs the server OS will do... an oldish laptop?) then I'd say go for it.

[zag]

Yes always virtualize.

 

Helps massively with the disaster recovery procedures.

[teejay]

8gb RAM is a very low amount of RAM for a server, especially if you're virtualising, probabaly too low to split your servers as you'll need memory for the Hyper-V server, then memory for each

As for virtualised DC, if you're sticking with 2003 R2 then the recommendation is to have one physical. If you're upgrading to 2012 R2 then go virtual as that is fully supported and changes in how AD works means you no longer have to worry about timing issues.

[seawolf]

That server is not adequate for virtualisation. You're going to be running three Windows servers (host and two VMs) with only 8GB of RAM. Most laptops sport that amount of RAM these days.

 

I would only consider virtualisation if you can bump the RAM up to 16GB or more and have a server that can backup and store the VMs. If you don't have backups of your VMs then you are more likely to have failures than with physical servers.

 

Sometimes virtualisation software can have problems, either from upgrade issues or bugs (seen both), and these can sometimes cause your VMs to be unbootable. I've had it occur with 3 VMs over 5 years with vSphere (v4.0, 4.1, 5.0, 5.1, 5.5). Easy to fix if you took a backup before major upgrades, DIW if you didn't.

[tmcd35]

8gb RAM is a very low amount of RAM for a server, especially if you're virtualising, probabaly too low to split your servers as you'll need memory for the Hyper-V server.

 

I'd point out he's running max 62 clients in a primary school. He'd could half that RAM and still do virtualisation with Hyper-V and not notice. Not that I'd recommend that of course. As it stand he could have 2Gb for host, 3Gb each for DC and File Server. Actually if you do it at all, ESXi would be a better host OS choice. Bump each guest OS up to 3.5Gb, ESXi shouldn't need more than 1Gb (it shouldn't really need half that).

 

DR is about the only compelling reason I can think of to consider it. I'm not sure it's a strong enough reason in this instance.

[jmak]

I am planning to do something similar. I've tested but not had a chance to make the change yet so can tell you my reasons, but can't report real world experience. The main difference is that I have upgraded the RAM from 4Gb to 24Gb in preparation - I know that's way more than I need, but it wasn't significantly more expensive than smaller upgrades when o bought it.

 

My main reasons are:

 

1) DR

2) Testing - I can try things out on a snapshot without making changes to the live server.

3) Potential to split out roles

4) simplified upgrade path when it happens - I will add a second server to the domain, promote to DC and demote the original. Would be even easier if I split out the file server role first

 

Just my thoughts - I know that not everyone will agree...

[PotNoodleTech]

Even though it's only got 8GB RAM, I'd still put VMware on it and set it up as one DC with 4GB RAM and one File Server with 4GB RAM. Vmware will only use ~1GB RAM which leaves plenty for your two VMS

 

Divorcing the physical hardware from the O/S is the most important benefit of Virtualisation.

Quick and easy backup/restore/migrates are the next most important benefit.

 

There are no downsides (to using VMware, Hyper-V is not so resource efficient).

[sparkeh]

Of course every instance is different but running a larger primary school's virtual environment, I would say that 8Gb could be used to do what you want. I would advise more but it seems that the 8Gb is set.

 

2Gb for host and 3Gb per server will be ok. I doubt the statement that "Most laptops sport that amount of RAM these days", certainly not in my experience anyway (just a non-scientific visit to Amazon shows that the vast majority of laptops are shipped with 4Gb).

 

I think DR is a major reason to virtualise and would highly recommend it. So if you go down this route put a lot of thought into this area as well.

 

As always I know people will be vehemently opposed to the above but I stick by it

Edited July 1, 2014 by sparkeh

[SYNACK]

Even though it's only got 8GB RAM, I'd still put VMware on it and set it up as one DC with 4GB RAM and one File Server with 4GB RAM. Vmware will only use ~1GB RAM which leaves plenty for your two VMS

 

Divorcing the physical hardware from the O/S is the most important benefit of Virtualisation.

Quick and easy backup/restore/migrates are the next most important benefit.

 

There are no downsides (to using VMware, Hyper-V is not so resource efficient).

 

Both have memory dedupe so if you have multiple servers all running the same base OS they can share 8GB nicely with only the differences taking up more memory. Hyper-V does use a bit more RAM for a host if using the full GUI version but it does give you a gui on the box itself where as you always need remote management tools on ESXi, you can use remote management tools on Hyper-V too to cut down the ram usage of the host by pulling out the GUI - this version is also free (no need for server 2012). ESXI is much nicer for Linux OSs and maybe has less updates along with not really needing a virus checker. Hyper-V really should still have some form of AV which is probably its biggest downfall as a host. You do get more advanced features for free with Hyper-V though like free live migration.

Edited July 1, 2014 by SYNACK

[edutech4schools]

If this is going to be your only server I would advise against this. You should have one DC on a physical host and virtualising adds an extra layer that can go wrong. I can understand going virtual if you have backup servers and SANS that can kick in automatically but you do not.

[Jawloms]

Thank you all very much for all your responses on this. I don't think I'll bother virtualising at this point as it will simply be a DC and have some file shares and I don't want to do it just for the sake of it. If it's anything like their current server, it will get set up, then left alone for six years, and then be replaced.

[johnhart96]

Please dont use Hyper-V. It is too risky having a full windows operating system between the VMS and the hardware. Vmware ESX is the most stable. We have had it for over 5 years now and it is completely bullet proof.

[localzuk]

Please dont use Hyper-V. It is too risky having a full windows operating system between the VMS and the hardware. Vmware ESX is the most stable. We have had it for over 5 years now and it is completely bullet proof.

 

Nonsense. Hyper-V is now a tried and tested, reliable, hypervisor. It is available in full OS form, or as a trimmed down hypervisor too.

 

I've been using Hyper-V for, what, 3 years and it also is bullet proof.

[SYNACK]

Please dont use Hyper-V. It is too risky having a full windows operating system between the VMS and the hardware. Vmware ESX is the most stable. We have had it for over 5 years now and it is completely bullet proof.

 

Thanks for your opinion but I have had Hyper-V machines running since 2009 and they have been perfectly decent, both solutions have merit and are used on many places. For bigger implementations Hyper-V actually offers more features for free than ESXi stopping you from delving into the expensive end of the pool but lets not drag this thread off topic any further with a played out debate about virtualisation solutions.

[johnhart96]

Appreciated that in server core hyper v is pretty stable, but I mean that when you are using Hyper v as a server roll in full windows server.

[localzuk]

Appreciated that in server core hyper v is pretty stable, but I mean that when you are using Hyper v as a server roll in full windows server.

 

Many people do this, like I do, and it is perfectly stable and reliable. You just don't install anything else on it (ie. No running it as an application server or the like too), but then the same rules apply to ESX - it is just a Linux OS, and as such you can install other stuff on it too but shouldn't.

[SYNACK]

If this is going to be your only server I would advise against this. You should have one DC on a physical host and virtualising adds an extra layer that can go wrong. I can understand going virtual if you have backup servers and SANS that can kick in automatically but you do not.

 

You are forgetting perhaps the nice features that VMs offer even if you don't have redundant systems, like spinning up the system on a high speced workstation in half an hour or so from backup or migrating between an old and new server live with no down time. Virtualisations does add another layer but it is not an especially problematic layer and the general advice against virtualising DCs is based on people snapshotting them and causing problems that way or joining the host servers to the AD domain.

 

I like the fact I can save my backup NAS from the other end of the school and happily spin up the network on a couple of the library Multipoint servers if a car crashed through the server room or something.

 

At any rate I am glad that the OP has it all going now on the new box and can move on to other holiday jobs.

[Oaktech]

This, as the debate suggests is a difficult one. We are in a similar situation with our federated primary.

 

We have a single HP ML server, when it was set up Hyper V made us a bit nervous so we set it up as a standalone server.

[sparkeh]

Many people do this, like I do, and it is perfectly stable and reliable. You just don't install anything else on it (ie. No running it as an application server or the like too), but then the same rules apply to ESX - it is just a Linux OS, and as such you can install other stuff on it too but shouldn't.

Yep I have it installed as a server role (with nothing else installed) and has run happily for the last 5 years.

 

You are forgetting perhaps the nice features that VMs offer even if you don't have redundant systems, like spinning up the system on a high speced workstation in half an hour or so from backup or migrating between an old and new server live with no down time. Virtualisations does add another layer but it is not an especially problematic layer and the general advice against virtualising DCs is based on people snapshotting them and causing problems that way or joining the host servers to the AD domain.

 

I like the fact I can save my backup NAS from the other end of the school and happily spin up the network on a couple of the library Multipoint servers if a car crashed through the server room or something.

 

We have just the one server and Veeam makes a complete replica of the two VMs it runs on a high spec workstation so the network can be restored in a few mins. Its awesome.