Server Virtualisation.

[BoomAM]

Hi.
What do the admins amongst you think of server virtualisation?

Im currently drawing up a 5year plan for our network and server virtualisation interests me.

At the moment we have 3 servers, one network has a server thats the DC, has AD, DNS, DHCP & file servers, and a second server that has our ISA proxy, and SQL for SurfControl. A second network has a server that does the DC, AD, DNS, DHCP, File server & SQL for Sims.

So the idea would be to virtualise the 3 'old' servers, but still keep them to run backups of the VMs on in an emergency.

Now theres many pro's and cons to server virtualisation, but im wondering what all of your viewpoints are on it, from an administrators point of view.

I have my viewpoint on it, im just wondering what you think?

Thanks in advance all. .

 

[BoomAM]

Some good points.
We're gonna be buying new servers anyway, as a new Sims.net release soon needs a significantely more capible server.
For the same price as 3 servers, we could get one server.
For example, i did a test spec, and for the same price as 3 that'd do the job (cheaper in fact), we could get a dual quad core system, 8gb memory and 2Tb of RAID5'ed storage. More than capable to run 3 servers on?
Backup/corruption wise, the plan would be to backup the VMs once a week to a NAS on our network. Making main backups simple.
Then either having the data drives backup seperately to tapes from within the host OS, or, prehaps, having the data stored on our NAS's.

Its strange, as you have all put across some valid points, but the ntsysadmin gang also put across some good points, but with the opposite of what you guys say..

 

[BoomAM]

How much resilience have spec'd into your super-dooper box? What happens if you have a major hardware failure on it? You could power up one of your old boxes but do any of them have the horsepower to cope with the new version of your Sims software?

The HDDs would be raid5'd over about 8 300Gb SAS disks, and the PSU would obviously be redundant ones running off a high capacity UPS.
The Sims.net issue is an issue, but a small one, they could theoretically mange without Sims.net, or restricted to under 5 users, until the main server could be repaired.

The ease of upgrade/expansion/backup is a big draw for me in regards to virtual servers. There is the 'all the eggs in one basket' problem, but i think that could be overcome with a good backup/failure routine.
Such as, as said, keeping the 'old' servers ready with the last working VMs of each server on each.

 

[BoomAM]

Ahh, a school techy.

Vitualisation give plenty of benifits on a large spec system, esecially when you enter a disaster recover position. It's easy to recover VMs from the VHD or what ever Vitual hdd image you're using.

One thing to consider though, if you're running VMs make sure the server has a TCP/IP offload engine to ssave on CPU cycles, it really does make a difference, especially when you have three servers going for 2/3 NICs.

Vitualisation is a big thing at the mo, but with hardware coming down in price is the cost benifit really worth it?

O/T: BTW, how many clients do you manage?

Burnsy

Over the two networks, about 750.
The test spec i did, did include an offload engine.
As you've mentioned, its the recovery options thats the big plus for me.
At the moment i'd have to install 2003, then symanbtec backupexec, then spend hours if not days reconstructing the data.
With a VM based system its as simple as one file. Dont have to worry about permissions, boot records, hardware type, ect;

Prehaps one mega server is overkill for 3 servers. But we wont allways have 3 servers. With the correct choice in parts now, giving us upgrade options later, we could add more servers as/when needed.

Then theres the issue on deciding the specifics of the spec. Do i go for one all singing all dancing server with lots of cores, lots of memory and terabytes of storage. Or do i have the storage on an entirely different system?

 

[BoomAM]

750 workstations and only three servers? Really?

No, lol.
750 users.
About 250 workstations in total.
And that grows by about 30-40 every year or so.
So you can sort of see my reasoning for virtualised; easyier/cheaper to deploy new servers.

Where the storage is kept depends entriely on your backup solution and network avaliability. Do you want a storage server /SAN? Although personally I'd keep it in the same server and have some LTO3 tape drives to back it up.

Burnsy

How do you mean network availability? You mean network speed?

 

[BoomAM]

make sure the backup solution is able backup file that are "in use" else i assume it wont be able to backup the vmware image.

A good live imaging software would be able to do that i suppose.
Or at worst, which im happy doing, i can take the 'servers' off line.

Is an 8 core/8gb/2tb system overkill for our needs do you think?
Gonna start writing up the plan this afternoon.

.

 

[BoomAM]

At my school we've got 4 Windows 2003 servers running, two of which are virtual servers. 400-450 clients.

Works well although the virtual ones don't handle apple shares well at all, especially for our ancient OS9 macs!

What spec is the host machine?

 

[BoomAM]

Avaliability is dependant on speed/bandwidth, network trafffic at the time between both the host machine and other nodes on the network. Basically, how long it'll take the data to be backed up over the network.

Burnsy

The backups would be done at 6pm, after the places closes, should be done by next morning as long as there are gigabit links between the server and the backup area. Which there is iirc.

Without seeing how heavily your existing ones are running can't really say. But tbh I'd be suprised if you even use a quarter of that most of the time.

Thats good then.
Room for expansion in the future.
Might put our VLE in a VM as well, if i can get frogtrade to give me the details to do so.