£10K

[zag]

Yes you should virtualize, but that doesn't mean you need SANS or separate storage.

 

Buying 1 extra machine for backups or clones is enough for high availibility.

 

here's a pic of our setup. Pretty simple really. The 6th server is in a seperate location to prevent a "the server room burnt down scenario".

 

[Ric_]

*Cough|* Ebay *cough* 16 x HP ProLiant BL460c w/ 2x Quad-Core Xeon L5420 2.5Ghz BL c7000 Blade Server | eBay

 

Leaves you with £5k for switches, storage and a lot of power connections.

[broc]

There was a thread on here a while back which suggested we can make life very complicated for ourselves with technology

 

We used to run our school on 7 seperate physical servers until BSF came along. Now we have a SAN and a dual VMWare cluster configured for high availability, with dedicated iSCSI switches & redundancy all over the place. It was not cheap... the irony is that we are delivering no more useful services or functionality to our end users than we were before BSF; true, we can cope with failure with less down time (in theory) but in the 7 years I ran our old low budget network we had two server failures of around 1/2 day which took out part of our operation. One of these was due to a serverboard dying (requiring cannibalisation of another server), the other a disk failure in a RAID array that took forever to rebuild.

 

Virtualisation is a techies dream (& nightmare)..... where I work we are pulling out of our managed service , to do this I have to migrate from VMWare to Hyper-V, add another server to the cluster, add extra disks to the SAN, & we need to sort out local & offsite backups. It is going to cost ££££££.... & we still won't be delivering any more services to our end users.

 

Don't let technology blind you ...... I would happily go back to a simpler environment

Edited November 30, 2012 by broc

[Punkfish]

Hi,

I do not as a rule comment on this board, but in the face of such ridiculous and ill-informed comments that I have witnessed today, I cannot help but bring my many years of virtualisation knowledge in both education and corporate world to bear.

 

I will concede that a SAN is not technically required for virtualisation, but it should be considered as a primary component of any size virtualisation project. Not only does this system allow the flexibility to present storage dynamically based on need, but also the combined spindle count, cache and controller configuration in such a system will deliver a higher level of IOPS (which is the holy grail for virtualisation) , when compared to a stand alone systems.

 

Almost all SANs can also host file data directly using CIFS (SMB) while at the same time using iSCSI for VM disk presentation, which will be more efficient than creating file servers in the virtual world and then saving all the file data to disks within that environment.

 

This is in addition to the obvious benefits of "real" high availability, such as seamless failover in the event of a host failure and not having to rely on copies, most of which will only be in a “crash consistent” state, which does not guarantee a smooth failover.

 

In regards server specifications, having a large number of servers with a small amount of RAM such as 32GB is an inefficient waste of hardware has the rest of the system will never be stretched before you run out of RAM.

 

The whole ethos of virtualisation is to “sweat” the hardware to ensure the most cost efficient use of the investment, and buying servers like that will not accomplish this. It is best to buy say two (or three) servers with a large number of NICS to ensure sufficient bandwidth for both server and storage communication and with say 72GB RAM as a Minimum (96GB+ would be better).

This type of investment is not one you make every day, and your decisions will have to stand the scrutiny of time, so make sure you have all the information at hand before making this leap, and do not fall into the all too common trap of seeing how many servers you can get for the money.

 

Virtualisation is 90% thinking and 10% deploying, always remember to think quality before quantity and I am sure you will get the results you want.

[pcstru]

Virtualisation is 90% thinking and 10% deploying, always remember to think quality before quantity and I am sure you will get the results you want.

 

Good post and I'd agree with most of what you say. However, if you are budget limited (common in schools) then you will have to compromise.

 

@garethedmondson - don't forget to factor in appropriate UPS.

[garethEds]

*Cough|* Ebay *cough* 16 x HP ProLiant BL460c w/ 2x Quad-Core Xeon L5420 2.5Ghz BL c7000 Blade Server | eBay

 

Leaves you with £5k for switches, storage and a lot of power connections.

 

Spooky - just been speaking to a refurb supplier about these.

 

Gareth

[glennda]

Personally I would say 3 x hosts. then buy a large Supermicro machine and install Open-E for a SAN solution using SAS drives, Open-E do deals on server licensing for education on the cheap and you can build a large drive.

[jamesfed]

Take a look on the Broadberry website - you can do some pretty nifty custom server designs that would fit your needs.

 

Server 2012 with its 'almost real time mirroring' mode makes a SAN nearly useless as the data is duplicated between the two hosts and in small-medium installs this will be cheaper than having a SAN.

 

£10k will buy you quite a lot of nice kit but do remember you need software (if you don't already have Server 2012 cals through EES/SA) as well so don't forget to factor that in!

[localzuk]

Ok, as your post was a little aggressive @Punkfish, I think I need to give a bit of a reasoned response.

 

This obsession with a SAN is pointless. A SAN is a specific piece of technology, an appliance if you will. We have shared storage which does all of what you discuss, but using a normal server. It isn't a special piece of kit.

 

So, personally I'd say that we should possibly stop using the term 'SAN' and use 'Shared Storage' instead.

 

A 2 server + shared storage solution is totally possible on a £10k budget. You just have to choose your components carefully.

 

I do agree though about the need for shared storage, doing it with replication or the like is adding extra software complexity to the solution that is more than likely going to come and bite you in the rear at some point. Follow the 'KISS' principal. Which is why I went for a simple Windows Server 2012 + Hyper-V using SMB3 solution. It took barely 10 minutes to configure once Server 2012 and Hyper-V were installed. Creating a server and enabling failover is a matter of a few clicks. No need for iSCSI, which face it, most people don't have the experience of in schools to be able to diagnose if it goes wrong - but they do know about standard Windows shares.

 

There's no need for extra specialist storage server software etc.

[RTFM]

I was speaking to Luke @Millgate today and he is starting a HP offer soon, I think he said Monday (3rd December).

 

Might be worth a word

[Punkfish]

Hi,

 

I agree that the word SAN could be substituted for shared storage, however a SAN is an optimised device that will provide better performance for similiar money to a specced up server (I am obviously not advocatinh EMC, NetApp or other lagre vendors here).

 

In the end it will just as easily come down to comfort levels with the technology, and some peole may feel more comfortabele with server based storwage than trying to take on board a new storage technologies as well as virtualisation

[zag]

There was a thread on here a while back which suggested we can make life very complicated for ourselves with technology

 

We used to run our school on 7 seperate physical servers until BSF came along. Now we have a SAN and a dual VMWare cluster configured for high availability, with dedicated iSCSI switches & redundancy all over the place. It was not cheap... the irony is that we are delivering no more useful services or functionality to our end users than we were before BSF; true, we can cope with failure with less down time (in theory) but in the 7 years I ran our old low budget network we had two server failures of around 1/2 day which took out part of our operation. One of these was due to a serverboard dying (requiring cannibalisation of another server), the other a disk failure in a RAID array that took forever to rebuild.

 

Virtualisation is a techies dream (& nightmare)..... where I work we are pulling out of our managed service , to do this I have to migrate from VMWare to Hyper-V, add another server to the cluster, add extra disks to the SAN, & we need to sort out local & offsite backups. It is going to cost ££££££.... & we still won't be delivering any more services to our end users.

 

Don't let technology blind you ...... I would happily go back to a simpler environment

 

Excellent post that. I've always gone by the mantra of keeping things simple so they are easily fixed, easily replaced and dont cost much to upgrade.

 

The post below by Punkfish also makes some excellent points as well though. I certainly will consider in the future the idea of higher RAM/Less machines.

 

P.s. I bet my SSD servers have higher IOPS than any of your SAN's

[localzuk]

Hi,

 

I agree that the word SAN could be substituted for shared storage, however a SAN is an optimised device that will provide better performance for similiar money to a specced up server (I am obviously not advocatinh EMC, NetApp or other lagre vendors here).

 

In the end it will just as easily come down to comfort levels with the technology, and some peole may feel more comfortabele with server based storwage than trying to take on board a new storage technologies as well as virtualisation

 

I agree they are similar in technologies but disagree on the money part. A SAN costs a lot of money, plain and simple. A server with hard disks and Windows Server is always going to be cheaper, and the speed will be similar in the environments we work in.

[zag]

Also forgot to mention our 3000Volt APC's cost 2 grand each, the server cabinet another 2k and the Rack monitor and keyboard/mouse pullout the same.

 

So probably looking at 18k for the full virtualization rollout.

 

One thing to remember is you don't have to do it all at the same time. It can be built in stages.

[Ric_]

Spooky - just been speaking to a refurb supplier about these.

 

Gareth

 

I was half joking about that... the C7000 requires HUGE power inputs. The C3000 is a better bet (single phase and regular power connections) and the chassis will last forever so you could buy a second user/refurb unit with older blades (quad-core Xeons) and then upgrade the blades and networking later when funds allow.

 

The point @localzuk makes about it being shared storage and not necessarily a typical SAN is also very valid. Just make sure you have plenty of NIC links from the SAN to the hosts - a couple of decent switches for failover and port aggregation are a must. There are also some very competitive NAS solutions from the lieks of QNAP and Thecus which have Citrix/VMWare certification.

[FN-GM]

Have you considered ISCSI for shared storage? It will be cheaper.

[glennda]

If you have any questions regarding Open-E PM me and I can try and answer them. If you want to see how easy it is to use build a vm in virtualbox and you can test it that way.

[chazzy2501]

You can get a Dell Powervault MD3200i SCSI SAN with 6x500GB NSAS (posh sata) for £5,600 EX VAT.

 

(I hope you mean 10k ex VAT)

[TronXP]

Take a look on the Broadberry website - you can do some pretty nifty custom server designs that would fit your needs.

 

I used broadberry for our junior school server and san, they are great to talk to, to make sure you get what you need. They also do educational discount

[glennda]

I used broadberry for our junior school server and san, they are great to talk to, to make sure you get what you need. They also do educational discount

 

The engineers are pretty good too - a few of them did the Open-E course with me last month

[dhicks]

I will concede that a SAN is not technically required for virtualisation, but it should be considered as a primary component of any size virtualisation project. Not only does this system allow the flexibility to present storage dynamically based on need, but also the combined spindle count, cache and controller configuration in such a system will deliver a higher level of IOPS (which is the holy grail for virtualisation) , when compared to a stand alone systems.

 

The part that provides the high I/O is the spindle count, cache and RAID controller - for a typical school, a single (large) server will provide more than enough processor power, so there's really no point in putting those disks and RAID controller on the other end of any kind of network connection, just connect them directly via SAS / SATA. There's no point scrimping on the equipment, so buy brand-new multi-processor, dual power supply servers with as much RAM as you can afford (although, in the context of someone having £10,000 to spend now, you could always add more RAM later), but you don't need a SAN. The second server needn't be as well specified, just enough to run the essentials to keep your network running while you get the main server back up if it conks out. Dynamically presented storage (LVM or similar) is typically handled by the virtualisation system itself.

 

Real-time disk cloning between two physical locations is, of course, ideal, but in my experience most schools can accept maybe half an hour's downtime in the event of a diasaster while you boot up a VM on a second server, trading off that potential downtime against the cost / palavar of implementing real-time disk mirroring.

 

This is in addition to the obvious benefits of "real" high availability, such as seamless failover in the event of a host failure and not having to rely on copies, most of which will only be in a “crash consistent” state, which does not guarantee a smooth failover.

 

Being able to take proper backups from snapshots of virtual machines is a feature of the virtualisation system - you need something that supports quiesced snapshots, which the free versions of VMWare and XenServer both seem to do these days.

[glennda]

 

Being able to take proper backups from snapshots of virtual machines is a feature of the virtualisation system - you need something that supports quiesced snapshots, which the free versions of VMWare and XenServer both seem to do these days.

 

You can't use veeam on Free ESXI its not supported.

[dhicks]

you don't need a SAN

 

Sorry, that should probably read more like "the original poster probably doesn't need a SAN for the scale of system he's building for the budget he has". You might well be running a larger system, or one with higher processing needs - once you hit the point where you need more VMs than will realisticly fit on one server then you need shared storage. I assume you're over at Alton Sixth Form College, which I can imagine has pretty large-scale processing requirements.

[dhicks]

You can't use veeam on Free ESXI its not supported.

 

Thanks, handy to know - I've not used VMWare, I just vaugly assumed it was like XenServer where you can just SSH in and write whatever you want to/from the block devices associated with your VMs.

[synaesthesia]

You can't use veeam on Free ESXI its not supported.

 

 

Erm... we have been for yonks... works fine on our 4.1 and 5.whatever hypervisors.