Do i really need a san?
Essentially after a few opinions here, looking to upgrada a number of servers and weighing up the possible options.
We are part virtualized, but only with a few lower impact servers and locally stored on one hp proliant. As part of the wider picture i want to virtualize the rest of the servers, including exchange, sims, sharepoint, sql etc.
Initially 've been looking at things like dell powervaults m3200i which seem to be quite well received but not exactly the cheapest units. I would want to maximise the protection so dual controllers, multiple nics and so on and therefore don't want to save money by getting something that is not up to scratch and future proof.
I'm budget conscious and really wouldn't want to spending over 15-20k all in including the hosts (if possbile!!!).
This is where my second thought comes in of getting higher spec hosts with more local storage, losing the san and then maybe just get a new storage server for file shares. We don't have masses of need for file storage space, current needs are no more than 1tb.
Other than the failover abilities that a san would bring, is there any real need to get a san and nost just store the virtual machines locally?
I think it saves in the long run, if you ever need a new host add it to the SAN and away you go! these days you dont even need to getr a HDD for the host can run from USB.
THough I m on holiday I m confident the system will be up by the time its Monday because the hosts are clustered and will come up on another host if one goes down.
Need mroe space? stick another HDD into the SAN
This is a thing I've pondered over for a long time.
I've written a number of posts on here on how we're doing things here, but generally I have three hosts looking after 12 VMs in total that are all local storage. A SAN would be ideal as the benefits are obvious but the intial costs are pretty high when looking into it and we just didn't have the budget. When I needed to expand the storage on one of the VMs we went down the DAS (Direct Attached Storage) route in the end as it was essentially half the cost of getting a SAN installed.
If you got the budget, then great - but when I was getting quotes in, pricing was starting at around £9k just for the SAN unit which didn't include the hosts and the infrastructure needed. I shudder when I see what other Schools are spending on just one box which equates to almost half my entire budget.
Dot hills SAN's are very well priced Dot Hill AssuredSAN 3420C review | Storage appliances | Enterprise | Reviews | PC Pro
Getting rid of the local hard disk saves a lot on each server as well as going for R300 or Dl360 as opposed to the 2U models. Also could you go for single power supply on each server as that gets the price down.
No. SANs are for situations where the amount of processing power you need outweighs the need for storage, or you are simply operating at a large scale. Most schools have a smaller scale IT operation and have more need for server-based storage than they do server-based processing power. If you're going to spend money, spend it on a NAS - you can use whatever equipment you deem appropriate to get you a device with the capacity and performance you want, but I'd think any server with a decent hardware RAID card controlling 8 or so 2TB drives should do the average school. Ideally, you'd match that with a backup server that stored day-by-day backups and could take over as the main file server if needed.
Originally Posted by awesomeo3000
For virtualisation, I prefer Debian running Xen (the free, open source version) and DRBD, which lets you easily mirror your VM images between physical machines. If you have the space to install two servers you can have one simply mirror the other, ready to take over should the first one conk out. That's probably slight overkill in a lot of cases, and things like Domain Controllers have their own replication mechanism anyway.
Agree with DHicks in your situation I think a NAS would be best solution and concentrate your budget on the actual storage. The new Overland Snapserver DXI1000 fits the bill and is very cost effective. I will pm you details.
One of the best solutions for what you describe would be the SGI (silicon graphics) Origin 400 system
It’s a blade centre (made by Intel) with an integrated dual controller SAN, integrated dual switch Ethernet and dual PSUs etc.
Like a datacentre in a can
All fully redundant and all managed through a single GUI
It supports 6 blades in total, all of which can support up to two 6 core CPUs, 96GB RAM
So as much performance as you will need in almost all scenarios at the SME.
You get a 7.2TB SAS based SAN, which is virtualised so you just creat pools of RAID 5, 6, 10 etc and present virtual disks to the hosts in the chassis
This means that you can fail a blade over without worrying about where the data sits as all blades have access to the same virtual storage pool
(kind of like VMotion in VMWare but without the need for VMWare)
Circa 20k for 3 blades running 16GB RAM and dual quad core Xeons each
7.2TBs dual controller SAN
2 x 10 port GigE switch blades
Install takes about 30 minutes
Fully stacked this solution will scale to support a massive workload
Its used often for VM and VDI and certified with all the common app vendors.
Nice feature but a SAN backend with shared storage is still going to be way quicker to snap from one host to another as it just needs to push config and memory rather than the possibly long winded streaming of the whole vhdx from one server to another. Especially if one host drops unexpectantly.
Originally Posted by apearce
Cool feature but shared storage will still have its advntages.
But does the average school actually need that kind of processing power, and is a system based around a central SAN the best arcitecture for a small-to-medium enterprise like a school? For around £10,000 you could buy two servers with decent dual processors, 16GB of RAM and enough local storage each for most server applications. Then you could also buy a decent-sized (10TB-odd) file server and a second, larger capacity (if slower) file server to back the first up. The two sets of servers could be placed in separate locations and mirrored via the network, so if one server cupboard has a catastrophic failure (fire, flood, etc) your school's data is still safe.
Originally Posted by Millgate
Most applications used in schools are designed to run client-side - if there's a server component it's often just a licensing server or communications broker of some kind. Even for web-based systems, like the typical VLE or something like Espresso, the average mid-range server is more than capable of any processing that's needed, with the network's main task being to provide access to files.
For Exch, well 2010, idea was to move away from SAN, and you dont need a SAN for 2010 as you have features like DAG now.
If Virtual servers and Virtual Desktop aren’t important to you in the next 3 or 4 years, then what you describe would do the job but it's what i would recommend as it really good value for money. Obviously it depends on budgets etc :)
Originally Posted by dhicks
I think i'm looking more in this direction, pricing up a couple of dell R710s with dual processors and a good chunk of ram it seems like i could get them pretty well specced for 10k-ish which should more than cover our needs for processing power and space for actual server images. Along with that i could rebuild and upgrade an existing proliant dl380 as a 3rd and backup host. The file storage i can then continue to keep outside the virtual hosts on a separate nas or file server.
Originally Posted by dhicks
I just got 2 DL360 G7's with dual 6 core xeon and 24gb ram (ram was on offer) and 8 network cards for little over 6k. (2 72gb drives in each). But they support bigger drives and can take up to 7.2tb with 8 x 900GB 10K sas drives.
if you are looking at your data capacity and noticing it is running out, looking at your backup capacity and realising it ran out a month ago, currently trying to recover data from a ropey western digital firewire drive that everyone has been filling up willy-nilly and that has now crashed. then yes you need a san. and so do we.