dhicks

I was looking at this a month or two ago, and at the time Google didn't support Windows Server R2 (they do now). Also, there doesn't seem to be an available easy-to-use mirror-all-VMs-to-the-cloud feature for Google Compute Engine as there does for AWS and Azure for Hyper-V. Google's model of computing isn't really your enterprise IT bunch-of-Windows-servers stuff, they seem to be concentrating on providing a platform for distributed cloud-based applications.

Can you give us specific examples of what happened - are there some things we need to check on our own systems?

We're aiming to have VMs running locally but mirrored to Azure / AWS (probably AWS, looking at pricing). That way we should get local network performance but be ready in case of local hardware failure, and conversly it shouldn't matter too much if Internet access conks out for a while. Our server hardware is around about the same as yours (capable but aging), and we have around about the same usage, although somewhere under 600 in total (staff and pupils).

If I have this right, you set up two Hyper-V servers, each hosting a Storage Spaces array. You then create a Scale Out File System from both of those arrays and host your VM images on that file system. Make sure your file system is large enough to hold all your images - Windows will take care of replicating data between the two nodes, i.e. as long as you have enough storage space on each server you'll have a copy of all of your VMs on each server. In a situation where one of your servers conks out you might have to prioratise which servers to run, or reduce processors / RAM assigned to each VM, but it should be possible to run a functional Windows domain on one decent-sized server.

The main issue seems to be with enterprise SSDs - consumer SSDs seem to be able to retain data better when powered off. Does make me wonder if we'll see any system failures after the summer holidays, though - PCs with SSDs sat unused for 6 weeks in a warm classroom, we might see some issues on the first day back in September. However, as far as I can make out the drives themselves are fine, it's just the data on them that might get lost - we can just re-image a workstation.

That might be the advantage of Raspberry Pi's or similar - you just have to buy them and provide hardware to plug them in, configuring them is up to the pupils. You could do pretty much the same with Linux VMs, too - just create 8 Debian VMs, provide the pupils with SSH to connect to them and leave them to it.

To that list I'd add interoperability, especially with your VLE - you want your VLE to be able to read class lists and so on from the MIS and write things like grades back.

Word takes ages to open by itself, or takes ages to open when you double-click on a particular Word file to launch Word and open the file? We had some older Word documents that referenced an old file server no longer is use, on opening Word would wait for a minute or two until it was sure the referenced file wasn't going to open. You web-downloaded files might be having the same issue - fixed references to resources that Word can't get to for some reason.

You could give them each their own virtual machine to configure, or buy 8 Raspberry Pis.

That's quite a difference for something that I'd assumed would casue a small performance hit. Any idea why this ism exactly?

Would giveing it a larger CrystalDiskMark test be any good - give it enough data that any caches get full, then we're looking at raw disk read / write speeds? Is that right? I'd assumed hardware RAID controllers cached reads, along with a read-ahead buffer, or is all that simply left up to the OS these days? Any idea what happens if you use an SSD drive RAID array and a SATA drive RAID array as components in a Storage Spaces volume? Does it all go horribly wrong in some way?

That seems to be a solution for creating a specific type of videos, not a general video editing package. It does look handy, though - I know someone who might find that software very useful, I'll point them towards it. Just so you know, your obe-tag.com domain gets catagorised as "advertising" by our web filter, you might find it's seen as ads by other schools, too. easysketchpro.education seems to be okay, though. As we've resurrected this rather old thread anyway, I'd just add that we've recently installed Corel's image and video editing suite site-wide - it seems like good value for money as you get a vector editing application (CorelDraw) as well as a video editing package. I see Vimeo are advertising their "Pro" accounts a a fair bit these days, I don't know if that includes any editing facilities.

I'm aiming to keep storage as local to the processing hardware as I can, so I'm intending to keep our current hardware setup of dual-processor, 64GB+ RAM servers with space for 8+ harddrive caddies in the front. I currently have two servers being live XenServer machines, both mirroring to a third, and I intend to switch those over to two machines running Hyper-V with a Scale-Out File System on a Storage Spaces pool mirrored between them. My current issue with implenting this is that the HP server I need to get out of the rack to add a new disk controller seems to be somewhat wedged in... As you've pointed out above, we can then look at Azure / AWS or a mirrored machine in another school somewhere for offsite backup and diaster recovery services - no third-party solutions really seem to support XenServer these days, it's not really used much by the small / medium business market. Once I've got the main Microsoft-running enterprise IT hardware moved around a bit, I'll have up to 9 physical servers spare, with a total of 44 drives slots between them. That's 44 single-disk VMs ready to be load-balanced into one snazzy distributed application.

We wound up buying two sets - one with all headsets, one with all handheld mics, and you can swap between sets, although you can only use 4 devices (one per channel) at any one time.

At the scale that most schools operate, I'd go for direct attached storage on each server with replication between servers. We currently do this with XenServer and DRBD to mirror volumes between servers, but we're looking at moving to Hyper-V with Storage Spaces / Scale Out File Server, and using SSDs as part of a tiered storage solution on the Storage Spaces volume. I don't have our test server up yet as I'm waiting for some parts, but there's a discussion that you might find useful here: http://www.edugeek.net/forums/hardware/153336-new-server-sanity-check-spec-2.html XenServer / DRBD has served well for the past 7 years or so, but Hyper-V / Storage Spaces looks rather slicker and easier to manage, with a nice GUI-based configuration.

I can't make out the text on the receivers, but I'm guessing those 4 LEDs in the middle give you an audio strength readout, and one of the other LEDs is probably a "connected" indicator. If you turn the mic on and no signal appears on the receiver, and you've tried changing the channels and checked the batteries are okay, then probably your mics are simply not going to connect to your receivers - they are from different manufacturers. This doesn't help you much fix your current issue, but if you're thinking of buying new mics I can recommend the Chord sets: http://www.amazon.co.uk/Chord-Wireless-Handheld-Microphones-Presentation/dp/B00NHSAYIA/ref=sr_1_14?ie=UTF8&qid=1431341298&sr=8-14 Not the fanciest of mics, but you do get 4 channels and a compact all-in-one rack-mount receiver, and the equipment has proven to be robust enough in the last couple of years of assorted school productions, being used by both small children and adults.

Which DAP Audio microphone - can you give us a link to a product or a model number? Do the receivers have a "connected" LED of some kind, showing they are getting a wireless signal?

With 1GB of cache RAM? We have a similar MegaRAID SAS 9271-8i with 1GB of cache in a couple of our Dell PowerEdge R510 servers. We have 4 4TB disks in a RAID5 array in each server. A discussion on performance can be found in here, but my basic conclusion is that for small enough read / write workloads, a RAID 5 or 6 array with a 1GB on-controller cache seems to perform as well as an array with SSD drives available for caching. In our case, a "small enough" workload means the file server is capable of handling general file access (redirected home folders, shared file areas for office documents and images) for at least 100 simultanious users. Due to an issue with our backup script, at one point we were copying all files from the main file server to the backup server every day as well as being a general file server, and we found we started hitting problems with around 80 users logged on. Your RAID controller supports JBOD mode, so you could go for a Windows Storage Spaces volume, if you're setting a Windows server. Quick edit: Just thought - both those servers have a decent amount of RAM in, 64GB, some of which is also available as a cache for Windows file services. The all-files-being-constantly-read error probably rendered the Windows file buffer useless, so the 80-ish simultanious users figure is probably valid for a Windows file server with very little RAM, in practice a file server with a decent bit of RAM should probably handle more users.

What are you considering using a video mixer for - do you have a requirement for live-streamed video of some kind? I've considered one for our new stage setup - have four cameras around the hall to film a play / event, and someone sitting making a live edited-together recording of the event. It would save time on video editing afterwards - at the moment we record an event, then collate all the video footage and edit it together, and the whole process can take a fair bit of time. However, a live mixing solution is less flexible - you can fade between shots and that's about your limit, whereas with an editing suite you can add whatever effect you like in. The V4 EX only seems to support 480p video on 3 channels - fine currently for YouTube or DVD quality video, but might start to look a bit limited quite soon. You also wind up with HDMI cables run around the hall. For the money a video mixer costs I can buy 4 GoPro cameras to place around a hall, editing the footage together afterwards. If you need to actually live-stream video then you'll need a mixer, although I'd try and find something that can handle higher resolution than the V4 EX if possible.

Ooh - interesting. Just for comparison, I looked up a thread from December 2013 where I was looking at our then-new file server. In one post there I ran CrystalDiskMark on our file server: http://www.edugeek.net/forums/windows-server-2008-r2/128270-windows-server-2008-r2-file-server-performance.html#post1096575 The results on the left-hand image are for smaller amounts of (100MB) data, small enough for the RAID controller (which has 1GB of RAM, I think) to cache, so the read and write speeds you see there are really the speeds for reading and writing RAM. Increase the amount of data (1000MB) and you see the underlying speed of the physical harddrives (4TB SATA models). I think we agreed at the time I'd made the right choice in RAID controllers, and over the past 18 months performance has been fine - 100-ish simultanious users on our network, all with all their files on the same storage array, doesn't cause problems. Your results above, though, are for 1000MB of data, and show read and write speeds pretty much comparable to our RAID controller's RAM cache, but for actual persistant disk storage! Can I check - does your test server have a RAID controller with a cache, or an HBA card that passes through raw harddrives to the OS? What precentage of the traffic is handled by the SSDs - what's the speed / volume trade-off like? Any chance you can try with some 2TB or similar SATA drives? One thought brought on by reviewing those results from 2013 - the sequential read speed for my server is slower than the sequential write speed. Is that because this is a cached device, so there's a cache-miss overhead every time the machine does a read operation? If the RAID controller with a cache is taken out and replaced with a bunch of raw disks, with SSDs being used as the highest level of disk cache in the system, is there a (possibly quite slight) increase in performance - is the RAID controller just getting in the way?

I've just been trying to get our HP Proliant DL360 Gen8 set up as a Storage Spaces server today. I've had some difficulties with the disk controller, the built-in HP Smart Array p420i. This is a RAID controller, designed to present arrays of harddrives to the OS as single drives. Initially it didn't want to start up with four 120GB Kingston SSDnow 300 drives in, but a firmware upgrade seems to have sorted that out. We have the basic confiruration, with no extra RAM cache on the controller, which turns out means that the controller only supports creating 2 drive arrays. For Windows Storage Spaces, you don't want to pass RAID arrays through to Windows, you want individual harddrives. You can't do that with this controller, it can't pass "raw" harddrives through to the OS, it has to create arrays. No problem, you can create single-drive RAID-0 arrays (in the latest version of HP's management utility there's even a handy automatic function to make each drive into its own single-drive RAID-0 array), but of course you're limited to only 2 arrays. Therefore, it turns out, I'm going to have to buy a RAM upgrade (at around £150) for the controller just to try out Storage Spaces. And a RAID controller isn't really ideal for use with Storage Spaces, really you want an HBA controller of some kind - also, it turns out, around £150. You might want to bear this in mind if you're buying a new machine - if you're aiming to use Storage Spaces with it, you need to make sure the disk controller is suitible. One feature the HP p420i does support is SSD over-provisioning. If I understand correctly, this aims to increase the lifetime of your SSD by keeping some capacity back for replacing sections as they wear out. This might allow you to use cheaper SSDs instead of enterprise-grade ones. Also, as far as I can see, the whole point of Storage Spaces is that it is relisiant to failure - if a harddrive fails you chuck it out and stick a new one in, the system carries on without pause. A bit wasteful of harddrives, but if consumer SSDs are a third the price of enterprise ones and last half as long you're still ahead.

There was a similar thread recently (I've searched, but I can't find it) about enabling the command prompt - I think that thread gave some specific examples of security issues, along with how to solve them. Can anyone remember the thread, or give us a list of security vunerabilities that have no solution but to disable the command prompt? The suggestion by mats, above, sounds good - set up a Linux server and let pupils log in to that. If there's a later requirement for pupils to have their own web development area or similar you can use it for that, too.

You might do worse than Chromebooks - web browsing happens locally on the device, taking a load off your servers, and they are perfectly capable thin clients.

Looking at Internet connectivity in particular, we're currently considering which providor to go for. One providor gives a good price, but the length of the 5-year contract is putting us off - we'd much prefer a 3-year contract. I don't know if I would want yearly contracts, just from the point of view that you'd have to spend time every year re-negotiating a new contract.

You could just get 6 1TB SSDs drives at £300 each, so under £2,000 in total, and not have to worry about performance.