Virtualisation of Servers

[timbo343]

I am struggling to get my head around this whole virtualisation stuff. Normally i am one for doing it all myself but i fear that i dont know enough or where to start regarding it all now things are getting so complex.

 

Would anyone be kind enough to give me a list of advantages of Virtual over physical.

 

I take it i would need 2 hosts first and a SAN before i start with anything?

 

Also would anyone have a go at doing it themselves or would you get someone in to help you do it?

[nicholab]

Normally you need:

 

Management server/This is normally a DC as well.

VM host 1

VM host 2

SAN/NAS or DAS shared storage.

VM software Hyper-v, ESXi or Xen server.

 

It is possible with Veeam to just use two servers with each with the same amount of local storage to replicate between the two.

Edited February 29, 2012 by nicholab

[dhicks]

Would anyone be kind enough to give me a list of advantages of Virtual over physical.

 

Virtual machines are hardware independant, so you can move them between physical hosts with no problems - handy if you need to upgrade a server or for failover purposes. They are easy to back up - you can take a snapshot of the VM's storage state at a given moment and, while the VM keeps on running, take a full copy. Snapshots also come in handy when upgrading something on a VM - take a snapshot beforehand so you can go back a step if you need to.

 

> I take it i would need 2 hosts first and a SAN before i start with anything?

 

No, in a school I'd aim for a larger server with a decent multi-core processor, a lot of RAM (64GB?) and decent amount of disk space. You can have a separate NAS if you need the storage space, along with a backup server if you have the budget. Also if the budget allows, a second server to host VMs, preferably in a different location - you could probably get away with having that be a lesser specification than the main one, capable of just running your vital services (domain controller, etc) if it had to.

 

Also would anyone have a go at doing it themselves or would you get someone in to help you do it?

 

Setting up a VM host is dead easy, you just boot from the install CD and follow the instructions. We use XenServer here which takes a few minutes to install.

[cpjitservices]

One advantage...... POWER if you have 5 physical servers all powered up n running then they will use alot of power, 5 servers on one virtual host well your only power is the virtual host.

 

Virtualization is easy really, we have gone completely virtual now and thanks to VMWare vCenter converter you can convert a running physical server to virtual live.

 

I am straying away from VMware in favour of Xen/KVM it's free and very easy to use, migrating machines is very easy and works perfect.

[CyberNerd]

 

I am straying away from VMware in favour of Xen/KVM it's free and very easy to use, migrating machines is very easy and works perfect.

 

yes. I'm really kicking myself for buying VMWare essentials after looking at KVM.

The paid for/supported version of KVM has a similar interface to vmware, all the bells and whistles at a fraction of the price.

[cpjitservices]

yes. I'm really kicking myself for buying VMWare essentials after looking at KVM.

The paid for/supported version of KVM has a similar interface to vmware, all the bells and whistles at a fraction of the price.

 

Don't you find that it's alot less heavy than VMWare aswell, we have 2 servers one of them is maxed out resource wise the second server is running KVM and has the same VM's on it and its barely hitting 25% utilization.

 

 

Spread the word for KVM it's fantastic, now the bugs have been ironed out the free version is just as good as the paid for now.

[CyberNerd]

Don't you find that it's alot less heavy than VMWare aswell, we have 2 servers one of them is maxed out resource wise the second server is running KVM and has the same VM's on it and its barely hitting 25% utilization.

 

 

Spread the word for KVM it's fantastic, now the bugs have been ironed out the free version is just as good as the paid for now.

 

Indeed. The paid for version is circa £350 per processor. THe advantages seem to be; support, the gui and ease of supporting virtual desktops

[glennda]

KVM is brilliant. I use it across 4 DL360/380's with HP MSA2000FC performance wise it kicks VMware/Hyper-V's backside - before you ask i've tested it and ask google.

 

With regards to virtualisation the major benefits have been outlined about.

 

If you list down what you currently have - desktops numbers, server numbers etc we can give you a bit more of a guide to how we recommend you do the setup.

 

To learn more about virtualisation download one of the freeware platforms such as KVM/ESXI and have a play!

[morganw]

For paid support of KVM do you need to buy into Redhat or are there any other options?

Do you also get some vendor backed PV drivers for Windows rather than relying on the Virtio ones?

[glennda]

Do you also get some vendor backed PV drivers for Windows rather than relying on the Virtio ones?

 

for networking yes - there are different options for what it can use - Intel, Realtek i think are the main two. They use the drivers windows will pickup automagically. Its better to use those kind of drivers. For the physical hardware Ubuntu does its own thing and with windows drivers for physical hardware can be a pita.

[glennda]

For paid support of KVM do you need to buy into Redhat or are there any other options?

 

Why pay for support? its the whole point behind linux. If you need an answer its on the internet!

 

EDIT: maybe not the whole point behind it! I use KVM on Ubuntu 10.04

 

Touch wood I've never had a problem with KVM - our OCFS2 cluster is another story.

Edited February 29, 2012 by glennda

[CyberNerd]

For paid support of KVM do you need to buy into Redhat or are there any other options?

Do you also get some vendor backed PV drivers for Windows rather than relying on the Virtio ones?

 

KVM has been built into the linux kernel since 2006. So in theory anyone could support it but Redhat will offer the best support.

 

The windows graphics drivers are also written and supported by redhat.

 

Why pay for support? its the whole point behind linux. If you need an answer its on the internet!

.

 

The sourcecode is free. putting it all together might be a bit more tricky. Take a look at the attached presentation for some of the features of RHEV that you don't get in virt-manager etc.

new-rhev3.ppt

[cpjitservices]

I've been using CentOS to run KVM and ran into a few problems at first which became confirmed redhat bugs, however after compiling the latest version and updateing the kernel its brilliant no problems and its all free and some pretty big players use and recommend KVM.

[hit]

One of my setups is 2 x HP DL 360 G7's each with 2 x e5630 processors and 48Gb RAM, 2 x Readynas 3200's (24Tb) and the best of the old servers as a DC/VCentre.

 

Most of the shares are NAS shares (which took quite a while to get our head around the ACLs) but the 3200's will also let you create iSCSI SAN volumes as well for VMWare to use.

 

We have 6 production windows and 4 or 5 linux servers plus whatever we feel like popping up for testing spread across them and i don't think I have ever seen the CPU usage of either host go above 50% but I think thats because most of the file sharing is via the NAS boxes.

 

I seem to remember the original outlay for VMWare licensing was around £300 with about £100 p/a after for maintenance contracts.

[glennda]

The sourcecode is free. putting it all together might be a bit more tricky. Take a look at the attached presentation for some of the features of RHEV that you don't get in virt-manager etc.

 

I tend to manage things more from the command line so use Virsh. Virt-manager is good but not overly amazing. I'm looking through the list of stuff here Which provide centralised management (particularly oVirt). We run the servers on Ubuntu and one of the install options is Virtualisation host. This installs all the dependencies etc. The only thing you need to do is setup a network bridge which is fairly straight forward.

 

EDIT: just noticed Ovirt is mentioned in that powerpoint!

[morganw]

We run the servers on Ubuntu and one of the install options is Virtualisation host. This installs all the dependencies etc. The only thing you need to do is setup a network bridge which is fairly straight forward.

 

Do you actually get some kind of official Ubuntu documentation for KVM or Xen? When I've looked I've only ever found community based documentation that tends to be sparse and out-of-date.

[CyberNerd]

The Redhat docs for KVM are here.

 

Red Hat Enterprise Linux

[morganw]

The Redhat docs for KVM are here.

 

Red Hat Enterprise Linux

 

Based on that I'd be more tempted to have a go with CentOS, or do they reserve some of this software for people that are paying them?

[CyberNerd]

Based on that I'd be more tempted to have a go with CentOS, or do they reserve some of this software for people that are paying them?

 

The KVM stuff is all free and built into linux.

 

I'm not really sure how much of RHEV 3 is 'free' presumably you can download it like you can with JBOSS. I've not found link so am thinking it is a 'package' that redhat sell unless you build from source.

[glennda]

Do you actually get some kind of official Ubuntu documentation for KVM or Xen? When I've looked I've only ever found community based documentation that tends to be sparse and out-of-date.

 

I use Community docs - most of it makes sense but sometimes you have to combine various resources to get something working correctly. But trust it fully everything sits atop - exchange, DC's, sims the lot

[morganw]

I use Community docs - most of it makes sense but sometimes you have to combine various resources to get something working correctly. But trust it fully everything sits atop - exchange, DC's, sims the lot

 

Do you have any issues with Ubuntu package updates? Personally I would feel happier using Debian because you know things aren't going to get changed other than fixing things and security for 2 or 3 years. I've heard a few people say that Ubuntu updates are a little more "dynamic".

[glennda]

Do you have any issues with Ubuntu package updates? Personally I would feel happier using Debian because you know things aren't going to get changed other than fixing things and security for 2 or 3 years. I've heard a few people say that Ubuntu updates are a little more "dynamic".

 

No only run servers on LTS Versions currently 10.04 and update every 6 months. We do heavy googling before updating to make sure there are no problems. Been running this for just over 2 years now. Started with 8.04 and moved up to 10.04. Will probably go 12.04 sometime in August. We don't run any gui's on the servers therefore this reduces the updates which come down significantly.

 

Sorry for Hijacking the thread!

[cpjitservices]

in centos you install the virtual server tools package upon installation and do a yum update when you boot into centos, or just add the package manually and do a kernel update.

[garethEds]

I am struggling to get my head around this whole virtualisation stuff. Normally i am one for doing it all myself but i fear that i dont know enough or where to start regarding it all now things are getting so complex.

 

Would anyone be kind enough to give me a list of advantages of Virtual over physical.

 

I take it i would need 2 hosts first and a SAN before i start with anything?

 

Also would anyone have a go at doing it themselves or would you get someone in to help you do it?

 

We are currently looking and costing the same as you @timbo343. We have decided on 2 hosts and a SAN and will be going towards Xen - plenty of advice on here for that. We are looking at the middle license which does cost money but adds some extra bits to the free version (we are still discussing this).

 

In addition we are going to budget for a kick-ass UPS to power all of this. (Still researching).

 

We are going to do this ourselves and with questions asked of Google and Edugeekers. We are not sure what to do - but have setup a little test network of two machines in a cluster to trial. We are currently running the trial and it seems to be okay.

 

The main issue is we have no idea if we are doing this right. Are we wasting money? Are we going to be okay for the next few years? We are replacing 7 servers (hangover from RM days and 4DCs) and moving them onto two servers. We will be moving a printer server (pCounter), an SME server and a few other bits.

 

We don't have a DC onsite - there are central DCs in the LEA - however due to the outage issues in Swansea LEA last week we feel that a DC on site would help. Can this be virtualised? I've heard/read on Google that DCs should not be virtualised, however as this isn't a 'main' DC I got the impression that it didn't matter. It's the one main DC that shouldn't be converted. What are the opinions on this?

 

Many thanks

 

Gareth

[cpjitservices]

DC's not virtualized ?? Never heard of this it makes no difference in fact I'd recommend you do!!!! For a start it means if need be you can move VM's from Server to server if you needed to do an upgrade etc etc - Our DC's and Exchange servers are all virtualized ..... I wouldnt recommend otherwise and definitely have one on site!