Will my solution work? (DV-PAL, AFP, GigE, Education)

[Matt Geier]

Ben,

I’ll take some time and give you a reply that will help you here.

– An independent Mac Pro to act as server. Entry-level model. Will only serve video, nothing else.

* 1Ghz of Processor to every 1 Gigabit port. If you follow this rule, you will be able to power your gigabit ports at full speed. If you don’t have enough processor power, it’s hard to say if ALL the ports will run full speed or not.

* 1Gb of Memory for every 1 Editor. If you are planning on 15 editors, you want 16Gb of Memory. If you follow this rule, you will have enough memory in the server for Final Cut Buffering.

(If you had Pro Res requirments, I would have said 2GB for every 1 Editor)

– Shared across network via AFP

* Yes

– Mac Pro Apple Hardware RAID card with 4x Apple SATA 1TB drives set up in RAID-0 (Backup done externally)

* When this is the idea, it’s hard to say if it will work 100% under all conditions.

If you look at this strictly from a disk bandwidth perspective, the bandwidth should look okay. Where people in video editing should also be concerned, is how fast the information get’s to and from the disks. This is called latency. It’s very hard to know if this is a good set up for low latency. If had to place a guess, this would NOT perform under low latency requirements like what Pro Res HQ requires.

It’s likely at some point you could break this with DV work too, you’d just need to throw enough at it to decide what that breaking point is.

As you said, you tested this with 5 streams of DV.

Keep going to find out what the breaking point is, and be sure to try various video formats because each one runs a little differently on the wire.

The more users hitting the RAID, or any Storage, will decrease the performance over time with the more you stack onto it.

– Small Tree 4 port network card with jumbo frames set up on both clients and server, all plugged into switch with link aggregation set up

* Small Tree’s 4 Port Gigabit Ethernet Adapter will have 400MB/sec of bandwidth with all four ports aggregated.

* Small Tree’s 6 Port Gigabit Ethernet Adapter will have 600MB/sec of bandwidth with all four ports aggregated.

– Entrasys 1Gb/sec Managed switches which support jumbo frames and link aggregation (I insisted on a Small Tree one, but education will only use Entrasys models because of an agreement they have with local suppliers, argh)

* If you are using something that’s not recommended, be sure it can support your requirements before approving the install.

* The switch should have 0.75 MB of Packet Buffer Memory Per Port – this is very important for Video Editing.

* The switch should support Dynamic Link Aggregation. This generally is a configurable item on Managed Switches. Typically Static is the default. Currently under 10.5 Apple ONLY supports Dynamic Link Aggregation. This falls under the 802.3ad specification, however, you need to check with the manual or the vendor to find out exactly how the switch you has supports it.

* The switch must support Full Duplex Full Control must also be able to work correctly. This would be Flow Control forward and backward (end to end).

Now i’m not even beginning to think that this would handle 100 machines, not even close. I’d very much hope it could handle up to 15 simultaneously (working on different projects). On paper this should be possible should it not, as DV-PAL is around 30mbit/sec, but obviously there are latency issues and other bottlenecks which i’m sure could cause slowdown.

Even if you did want 100 people all working at once. You would NEVER put them all on this ONE CONFIGURATION. You would at least use two servers and two raids and network them together. Go back up to my comment about putting a lot of users on RAIDs. The more you have, the less performance you get from your RAID.

I hope this doesn’t seem like a stupid setup, but based on what i’ve written above, could i get an estimate on how many simultaneous streams/clients this setup could handle? I’ve tested 5 simultaneous clients on our current setup which is a 100mbit network and an XServe and there appears to be no problem at the moment.

If you rely on just bandwidth math to accomplish what you want, you could use the following as a basis.

A gigabit wire is specified to run at 100MB/sec, however, under Apple’s AFP, we can use Jumbo Frames and Reach a wire bandwidth of about 80MB/sec (Allowing 20% overhead for other i/o’s etc..)

80MB (One Gigabit Wire) Divided By 3MB (DV25) = 26 Streams of DV25
80MB (One Gigabit Wire) Divided By 7MB (DV50) = 11 Streams of DV50

4 Port Gigabit Ethernet Adapter will have 400MB/sec
Use 320MB because you minus 20% from 400MB

320MB (Four Gigabit Wires) Divided By 3MB (DV25) = 106 Streams of DV25
320MB (Four Gigabit Wires) Divided By 7MB (DV50) = 45 Streams of DV50

6 Port Gigabit Ethernet Adapter will have 600MB/sec
Use 480MB because you minus 20% from 600MB

480MB (Six Gigabit Wires) Divided By 3MB (DV25) = 160 Streams of DV25
480MB (Six Gigabit Wires) Divided By 7MB (DV50) = 68 Streams of DV50

WORD OF WARNING – I would NEVER Recommend or Suggest ever putting this many users on one Server or one Raid due to the performance issues that can cause various hiccups.

It would always be best to split the users evenly across servers and raids to perform at “best/optimized” conditions.

I hope this helps you,

Matt G
651-209-6509 x 1

[Bob Zelin]

Ben,
I will respond in detail, but first let me give you an aggresive lecture. IF YOUR IT DEPARMENT WONT HELP YOU, AND YOU DONT LISTEN TO US, NOTHING IS GOING TO WORK. This stuff does not just plug in and work. Your IT deparment is insisting on Entrasys switch. If you, or your IT deparment can get Entrasys on the phone, that’s great, then it will work. But if NO ONE (you or your IT guys) cannot configure the switch for Dynamic Link Aggregation, with jumbo frames and and flow control, then IT WILL NOT WORK. This applies to Netgear, Linksys, HP, and all the others. Cisco and Netgear make great products, but if no one can assist you with all the GUI interface menu setups, then you will fail. When you buy anyones products, even Apple XSAN, or EditShare you are paying for SUPPORT to assist with the setup. No support – you get screwed.

I will respond to your comments below –

YOU WRITE –
Our only problem is, despite this being an essential for our department to run, education will not supply us with quite the amount of money we need to set up an optimal solution or even get any professional consultation. So we’re having to be as economical as possible and guess a lot of things. Therefore no upgrading of our building to fibre networking, we’re stuck with CAT5 ethernet in our walls.

REPLY – Cat 5 ethernet will work just fine, but you CANNOT HAVE your normal network (internet access, email, etc.) on the same ethernet network. If you don’t have a DEDICATED ETHERNET PORT for this application, that you can assign a static IP address to, you are wasting your time. I know every well the nightmare involved in running 100 extra ethernet cables to every MAC. The expense of this is greater than all the equipment. But if you can’t dedicate an ethernet port for this application, you are just wasting your time.

– An independent Mac Pro to act as server. Entry-level model. Will only serve video, nothing else.

REPLY – this will work.

– Shared across network via AFP

RPELY – this will work.

– Mac Pro Apple Hardware RAID card with 4x Apple SATA 1TB drives set up in RAID-0 (Backup done externally)

REPLY – you don’t need the Apple RAID card. Stick some drives in there, use Apple Disk Utility to stripe them RAID 0, and be done with it. Unless you want RAID 5, you are WASTING YOUR MONEY on the Apple RAID card.

– Small Tree 4 port network card with jumbo frames set up on both clients and server, all plugged into switch with link aggregation set up

REPLY – get the Small Tree PEG6, not the PEG4 for your application.

– Entrasys 1Gb/sec Managed switches which support jumbo frames and link aggregation (I insisted on a Small Tree one, but education will only use Entrasys models because of an agreement they have with local suppliers, argh)

REPLY – THIS IS YOUR #1 problem. Unless your LOCAL SUPPLIER is an expert at the Entrasys model, and can ASSIST YOU WITH THE SETUP for dynamic link aggregation, flow control, and jumbo frames, YOU WILL FAIL. If you think you will figure this out by yourself, you are dreaming. I could not do it without direct support from Entrasys. It is my suggestion that you call Entrasys, and get this information RIGHT NOW, and if you can’t, just give up, because you will waste the schools money, and you will get fired.

Now i’m not even beginning to think that this would handle 100 machines, not even close. I’d very much hope it could handle up to 15 simultaneously (working on different projects).

REPLY – at DV25, you can do 15 systems. This is the most you will be able to do.

On paper this should be possible should it not, as DV-PAL is around 30mbit/sec, but obviously there are latency issues and other bottlenecks which i’m sure could cause slowdown.

REPLY –
DV PAL is not 30Mb/sec. It’s 3.7 Mb/sec. If you use the Small Tree hardware, you will have no issues.

I cannot begin to stress to you, that if you cannot get direct support from Entrasys, you are wasting your time, and money.

Bob Zelin

[Matt Geier]

et all,

For sake of clarity here because there’s a lot of Mb and MB being thrown around. For those that know this already we don’t tend to worry about because we generally know what “is implied” when it’s not stated correctly.

Without further rif raf…

Mb = Megabits
MB = Megabytes

1Mb (Megabit) = 0.125 MB (MegaBytes)
1MB (Megabyte) = 8Mb (Megabit)

If you have a 30Mb (Megabit) then you could also say you needed 3.7 MB (Megabyte) of bandwidth.

Matt G.

[Bob Zelin]

then what is mb (not MB, not Mb)

bob Zelin

[Ben Pirouet]

For a start, I’m very grateful for the detailed replies, many many thanks!

Luckily the one advantage of our local supplier deal is we can have consultation on the Entrasys switches, and they are experts on the model. I am not under any illusion that i could configure such a switch for optimal performance myself, i always did intend to have them set it up for me based on our requirements.

Thanks very much for pointing out the non-necessity of the hardware RAID card. I can use that money and spend it on the extra cash needed for the 6 port Small Tree card. I knew you could do RAID-0 in Disk Utility in software, but i assumed a Hardware RAID card would handle it better and take pressure off the main processor. I imagine that’s true for RAID5 and all, but not necessary for RAID-0.

I am doing further testing on our current setup, and will post the results here. But so far you’ve given me a lot to work with. Again thanks very much.

[Ben Pirouet]

I hope you don’t mind me bumping up this thread, but i just thought i’d update you on our progress of this solution.

It is now installed, and working much better than expected, more on that later.

We changed the specification slightly after begging education for some more money, this is the solution we ended up with.

XServe 2.26ghz 8-Core with 6GB RAM, 3x 1TB Apple Drive Modules running RAID0 with external Time machine backup running on a couple of FW800 backup drives, as of course running a RAID0 is very fast but fatal is one drive fails. We have a spare ADM on standby should one ever die. We used an SSD drive as the OS drive of course so no extra stress was put on the RAID other than the video. I know using a Time Machine FW800 drive as a backup is not very ‘professional’ but we’ve used Time Machine as our backup on our main server with some USB2 drives, and it’s absolutely faultless, we’ve saved many a students data because of it. I doubt any paid solution could improve upon it frankly.

The rest of the spec remains the same as my original post. Like was suggested in this thread, we made sure when the Entrasys switches were installed, that we got in a network engineer who knew exactly what he was doing. He enabled the Jumbo Frame support on the Entrasys switches as well as setting up LACP for the Link Aggregation. We got the 4 port SmallTree card as well of course, our supplier couldn’t get hold of the 6 port.

After installation, on the first week of the new term we asked our students to do some stress testing for us and i was quite frankly shocked by the results. We had 28 students on 28 clients, half of which capturing footage from DVCam tapes on VTR’s and half were using existing files placed on the new server and were told to edit away, put multiple clips on top of each other in FCE without rendering, and of course adding effects and rendering. Really pushing the server. DV25 footage only.

After checking the logs afterwards, the maximum percentage the CPU was being used for over the course of the hour long test session was 2% and the maximum throughput the network card was putting out was about 50 megabytes per second or 400mbps. We have an aggregated 4gbps network card and only 400mbps was being used.

After being so worried that the server could not handle the massive influx of data that one group full of students would put on it, having 2 full groups (28 people) barely touched it. I didn’t really believe the results, so i checked the Scratch Disk settings on all the clients, checked all the students had actually done what i had asked them to do and they had.

So i’m very happy that this solution has worked, and even gives us room for expansion to compressed HD sources in the future.

Just like to add my thanks for the helpful suggestions given on this forum, i’d have been lost without them.