Dave_O (24th October 2011)
Not having a great deal of knowledge or money available 2 years ago we decided on the virtualisation route and for various reasons chose 2 different SAN's, our setup also differs from most as quite a few people have gone down the ESX route we decided to go down the Xenserver route and our choice so far has been vindicated.
We are not a large school with approx 700 students and 50 teachers plus other staff which totals in all approx 1000 end users, 350 workstations plus approx 50 laptops.
Setup is 3 hosts (Dell 2950s with 73Gb mirrored 15000rpm SAS drives and 32Gb memory, 3 x twin nics + Dual fibre nics if needed + dual PSUs) these are attached through 2 x 1Gb managed switches (For failover) For the SAN backends we have 2 models as I have stated, one is the Hitachi SMS100 (50,000 IOPs) for user storage which gives us 6Tb of formatted storage using raid 6 and the other SAN for our VM's is a Sun 7110 with HA coupled to a temporary NAS box until we can afford another secondhand Sun 7110 to match our own or something that will allow us to mirror our existing Sun 7110 with.
We have 17 servers across the 3 hosts including our Sims and Zimbra e-mail service which are IOP intensive, we migrated in February this year to Windows 7 and since have found our login speeds have come down just a few seconds to around 35 secs for new profile and if user logs off and back on again comes down to approx 5 secs. Our Sims login from enter to home screen is around 11 - 15 secs depending on which workstation you are on in the school as we do have some older P4s (around 30 which we have been testing with SSDs at £70 each, this greatly increases the speed to that of our fastest workstations). We do still have our DC and secondary DC as physical boxes as we see no reason to virtualise these at the moment as they are on quite new hardware.
HA for above £400 per host
3 x Dell 2950s with all extra's £1800 each
1 x Hitachi SMS100 SAN £6k
1 x Sun 7110 SAN £7k
2 x Gb managed switches £140 each
Total just over £16k
We find things so much easier now in doing the most simplest of things to the most complex.
We may not have the most expensive or the most elaborate setup but it works very well indeed.
Just though I would share that with people who don't have too much money to spare.
Dave_O (24th October 2011)
Yes point taken.
Really interesting and informative post. I looked at Xenserver when I started all of this virtualisation lark but did not have the guts to go down that route (too old, decrepid and risk aversed). As I have posted before, if you stick to big name brands you won't go far wrong. I too have a Dell 2950 that I use to support the VDI solution it's been around for 5 years and never let me down once. You have a well thought out resilient solution which is appropriately priced for you situation (Now I sound like Ofsted!).
My problem is that I find it easy to convince people to spend money, usually because I've done my homework and relate expenditure tenuously to educational need but mainly because I've taught for 21 years, staff are scared of me and I frequently play the "I've been there and feel your pain" empathy card. I need to be kept under control!
HyperV on 2008 r2 is quite mature I had XEN server to start with, it was Ok but be careful of the upgrades!
Xenserver has improved enormously and is now at version 6, as long as you have a good system setup then it's a re-install of the Xenserver OS and connect back up to the connected storage.
Its when you have local storage that it could become a problem and updating your hosts in the required sequence is key.
Will take your advice onboard though.
Even Hyper-V has its problems with upgrades according to some people, you pays your money and you take's your choice.
Its a bad sign when citrix are trying everything to support other management tools like sccm 2012 look how Borland Delphi turn out when it supported .net!
Citrix was good but so much had to be added on like backing up for example plus a bad upgrade happened to me last year with not much in event logs and little help in the citrix forums, thats my major gripe.
So whats happening with 6.0 then?
XenServer 6 – New Features:
Self Service Manager – This new feature (superseding Lab Manager) enables you to build self-service environments for “private clouds.” Self-Service Manager includes support for both XenServer as well as VMware vSphere
- simple virtual appliance and web-based UI.
- offers multi-tenant support for creating VM “service catalogs”
vApps- Virtual Appliance support. Within XenCenter 6.0 you can create multi-VM virtual appliances (vApps), with relationships between the VMs for use with the boot sequence during Site Recovery. vApps can be easily imported and exported using the Open Virtualization Format (OVF) standard
Microsoft System Center integration:
Starting with the XS 6.0 release, you will have the option of managing XenServer hosts and VMs with System Center Virtual Machine Manager (VMM) 2012. For more information refer to the Microsoft System Center 2012 beta page
- System Center integration is available with a special supplemental pack from Citrix (installed on XenServer hosts), which is targeted for general availability when System Center 2012 ships later this year.
GPU pass-through (formerly experimental support) – With the 6.0 release, a physical GPU can be assigned to a VM so the applications running in the guest can leverage GPU instructions (“GPU pass-thru”). This provides significant TCO benefits for the XenDesktop HDX 3D Pro technology used for delivery of CAD and other graphical applications via virtual desktops
Other (virtualizationmatrix-related) updates
Host RAM support has been increased to 1 TB
VM vCPU and vRAM support is increased e.g. up to 16 vCPUs and 128 GB RAM for Windows; increased Linux vCPU and vRAM support levels vary by distro
These are just a few changes: Some say that it may be Citrix looking to promote Microsofts SCVMM 2012 to which they maybe leaning towards but seeing as they have discontinued support for Citrix Essentials for Hyper-V could have been interpreted as effort to focus on its own XenServer management capabilities.
Its what you want from your Hypervisor that is key and I feel it offers a little more freedom than Hyper-V but that is just my choice.
I find the whole topic of claimed IOPs an interesting one. The IBM DS3500 claims 40,000 IOPs (with turbo mode) and as you state the Hitachi SMS 100 50,000 IOPs. Now reading the reviews of each unit on PCPro I see the following:-
DS3500 (without turbo mode)
"For performance testing, we started with a Broadberry CyberServe dual Xeon X5560 server running Windows Server 2008 Enterprise R2. We mapped it to a dedicated volume and saw Iometer report a fast 648MB/sec raw read throughput. We then added a Dell PowerEdge R715 dual Opteron 6100 server and mapped a second dedicated volume to it. With Iometer running on both systems we saw a cumulative raw read throughput of 1,280MB/sec."
Hitachi SMS 100
"For testing, we used a pair of Boston Supermicro dual 3GHz Xeon 5160 servers loaded with Windows Server 2003 R2 and Microsoft's iSCSI initiator. With one server logged into a data port on one controller we saw Iometer return a speedy raw read rate of 110MB/sec. We logged the second server onto a dedicated data port on the other controller and watched Iometer report a cumulative throughput of 218MB/sec for both systems."
"The 7110 proved quick, with Iometer reporting a speedy 112MB/sec raw read throughput for one iSCSI target. Running Iometer on two servers, each logged in to different data ports and dedicated targets, saw a cumulative speed of 134MB/sec showing contention for resources."
SAN metrics are not a straight forward topic. The best way to test, is in your own environment under real conditions.
You are totally right, unless you can afford to have consultants come in and design the system for you then it is what we ourselves perceive through our raw reading and learning skills plus our experience gained from what other professionals feed us through various mediums EG being one of them.
I don't profess to be an expert in any field, more common sense than anything.
With Virtualization I never been able to use it I as I was told:
RM don't support it
No schools use it
Has not been proven in use yet.
Can't virtualize DC/Exchange/SQL
Don't have the experience to manage a virtual environment.
I just feel I missed out now I work in a different environment and it is all cloud computing so I miss the VM boat.
1. RM are a liability, they need to move with the times. We have just supported one large secondary in moving to a virtual platform. They project a ROI within 3 years (set against the RM costs)
2. See above and it depends on the value you place in IT.
3. All of the fortune 500 organisations have a virtual infrastructure of some level. Not sure who's feeding you this information but they need to get their heads out of their collectives a**es. As stated above we have run virtualisation for the past 5 years, is this not proof enough.
4. Can't virtualise DC, Exchange, SQL WTF! What planet are they on?
5. Neither did I but you learn, that's what life and progress are about.
Never give up. If you feel it would be of any value I would be happy to talk to anyone who has objections to using virtualisation in a school environment, which lets face it isn't exactly demanding in terms of virtualisation kit. There are examples of a range of kit even on this thread to suit most size schools. If you want to arrange a visit with these people then again you are quite welcome. I can show implementations from schools with 2000 students and 1200 PCs down to schools with 800 pupils and 200 PCs.My guess is that the people voicing and hiding behind these objections do not want to invest and are scared of change. This is not a technology that is a flash in the pan, it is here to stay.
And two of us manage it all! I do the backend stuff the tech does the majority of the desktop stuff. We also have a very good program of using technically minded 6th formers 1 day a week (when they have say 2 lessons in the morning - the rest of the day is us) it's something to add to there icas reference.
We also have a group of 7/8 year 10/11 kids who are incharge of all equipment and setups for assemblies/parents evening etc.
1. RM are a liability, they need to move with the times. My predictions about migrating to CC4 versus looking at vanilla came true. I heard this from a friend who was teaching at the school after I left that it had been a nightmare migration.
It also came down to me trying to lead beyond the roll that people wanted me to have in their school.
I now work a SMB and things like that are not in the business plan for a while.
There are currently 1 users browsing this thread. (0 members and 1 guests)