How big can it get?

[brolling]

Hello, I've been talking to people about sagetv a lot lately, and I've built a pretty big system which seemed to me to be a bit of a feat at the time.

I'd like to know if anybody has run into a maximum configuration.

The system I built has 8 pvr-250 tuner cards, 5 on the sage server and 3 in a sage recorder machine. It also has 2 sagetv clients and a 1200GB RAID5 array.

If I were to go all-gigabit networking, offload storage onto its own machine, set up 30 tuners across 8 sagetv recorder machines, and run 50 clients, would that be technically possible, assuming the network can handle it? At what point does sagetv server start rejecting client connections? Let's assume that I'm recording at about 4Mbps per channel.

Thanks in advance.
BRolling

[Narflex]

Go for it....we have yet to have anybody find a limit that can't be solved with the appropriate hardware. The software itself doesnt have any limits. It is technically possible.

[indigo]

You're gonna need more than gigabit if you intend to do all that, there's no way it will sustain the sorts of transfer rates you need.

[stevech]

I wonder if the PCI bus can cope

[sleonard]

DVD Standard Play @ 3.2 GB/Hr X 8 b/B = 25.6 Gb/Hr X 1Hr/60m X 1m/60s = 7.1 Mb/s X 50 Streams = 350.5 Mb/s. (check my math, just in case ) Easily within GBit network and PCI Bus parameters but...

If the media is crossing the network from storage to the Sage server before being streamed then that # could double to 700 Mb/s. Now your approaching the real life limits of of the servers connection. (The servers connection is the only one seeing the full amount of Sage traffic on a switched network. A Client connection would still only see 7.1 Mb/s.)

It might be possible to use 2 NICs in the server, 1 for a subnet with all the network encoders and storage servers and the other for a subnet with all the clients but I don't know if Sage can handle multiple networks and NICs.

If multiple copies of Sage Server were able to stream their local content directly to the client instead of sending it to the main server first then the load on the main server would be drastically reduced. You would want each server to have local storage for its tuners and not a separate storage server though. Unfortunately a 2nd Server becomes merely a network encoder and doubles the bandwidth needed at the main server for every stream.

[jptaz]

I would say yoru math is close...I got 7.4Mb/s assuming 3.25GB/HR so 370 Mb/s.

But more importantly he said he was only going to do 4Mb/s recording quality so it is only 200 Mb/s

Still easily in operational parameter of Network...

But creating a storage server that can handle 25 Mega Bytes a second Random Writes and simultaneous random reads will be costly and the storage server / SageTV Server is going to have to be a good server class machine and really should be the same box since that will avoid a lot of network traffic since all the clients have to stream data from SageTV which should not have to go out to the network to read it. It should probably be a dual NIC server.

EDIT: The storage Server could and probably should be connected to an external storage box of some sort of fast interface like fibre channel or iSCSI etc and not just a TCP/IP and the reason I say it will be costly to get that performance is I am assuming a large capacity and it should also be RAID 5 or 6 and maybe for prformance 50 or 60.

If the SageTV recording path is set to \\<Storage NIC IP>\<Share Name> and then all the clients connect to <Client NIC IP> on the server then you are keeping the traffic for recording seperate from client communication and in fact I would setup the Sage Recording farm and the <Storage NIC> on a VLAN that is isolated from rest of the network that way it is not going to see any broadcasts or other traffic.

Just my thoughts.

John

[brolling]

Has anybody else set up a system with a completely separate file server? What I'm wondering is, which components (recorder, client, server) need to stream the data through the server in order to get it out to the clients or to record files to disk.

When setting up sage recorder you must identify a network share path, does this mean that it won't have to pass through the sagetv server on its way to the disk array? What about the sagetv clients, will they get file identifiers from the server and then access the file server directly, or do they get the data directly from the sagetv server?

I've noticed that when Windows (even 2003 server) has few processor cycles available (cpu at 95% and up), network operations tend to get a very low priority. This is the reason for offloading the file server functionality to a different machine. If we are going to build a system like this we will need to know exactly where the video streams are flowing before we start mapping the network.

I'm not concerned so much about using 700Mbps on a network, but we may run into trouble if a server is trying to sustain that kind of network and disk traffic, and update scheduling and playback data for 50 clients and 30 recorders.

If the data can stream directly point-to-point between each machine, maybe we can add HD
BRolling

[lotusvball]

Originally Posted by brolling

Has anybody else set up a system with a completely separate file server? What I'm wondering is, which components (recorder, client, server) need to stream the data through the server in order to get it out to the clients or to record files to disk.

I am using a file server connected to my network and my SageTV Server stores the recordings to the file server. Now I am using an MVP as my clients so everything runs through my sage server. No problems with 100mb network. I am buying two more tuners to put in the server and upgrading everything to gb network. The file server I use is just an old system with a program called NASLite + running off of a USB device. 2 TB of data and so far so good.

[brolling]

Originally Posted by lotusvball

I am using a file server connected to my network and my SageTV Server stores the recordings to the file server.

When you set up other sagetv clients I'd be curious to hear if they access the file server directly, unless somebody else is able to answer that first.

BRolling

[jptaz]

All Streamed files go through SageTV Server....so SageTV would have to go across the network and read the files from the file server and then send it back out to the clients. This would be ok if you had two NICs as I described and all the SageTV recorders, the file Server and one of the NICs of the SageTV Server were all isolated. So basically none of the Client PCs could communicate with any of the Sage Recording PCs not could they communicate with the File server.

John

[brolling]

Network traffic isues aside, can anybody think of other performance issues we may run into when putting this system together? Does anybody have experience with running 10 or more clients? The network speed issue I can solve with muti-linked gigabit network cards, and the storage will be a RAID array capable of sustaining over 200MB/s, so that system processor will be our only single limitation. Having it manage the network traffic at the same time as 50 clients and 30 recording channels might be hard for a single machine to handle, like walking and chewing 50 sticks of gum.

[Opus4]

BTW, I forgot about this too, but the client is supposed to be able to stream files itself w/o going through the server. If the recorded file's path is directly accessible by the client, it will play the recording w/o having to stream via the server. If that access attempt fails, then it will continue with the regular method of streaming from the server. The best bet for this would be UNC paths, but the client would still at least need read access to the location.

- Andy

[sleonard]

Originally Posted by jptaz

All Streamed files go through SageTV Server....so SageTV would have to go across the network and read the files from the file server and then send it back out to the clients. This would be ok if you had two NICs as I described and all the SageTV recorders, the file Server and one of the NICs of the SageTV Server were all isolated. So basically none of the Client PCs could communicate with any of the Sage Recording PCs not could they communicate with the File server.

John

All files recorded by Sage. I think I have read that imported media, Ripped DVD's, and/or music files get pulled directly from the file server but I could be wrong.

[jptaz]

Cool...I never knew the client was smart enough to bypass the Server like that.

Since that is the case for sure just make a big fast storage server. Really no single NIC should see too much taffic with the exception of the File Server....but as you mentioned it will be a multi linked Gigabit NIC so no issue.

Another solution to a single file server if you are concerned about that not handling the throughput is to have several file servers. In fact why not just make each PC that you are using for Sage Encoders be a storage server that way none of them should have too much load, unless of course all 50 clients try to watch the same recording at once, but I am willing to bet the OS file cache will help and the load will mostly be on the NIC and again if they all have GigaBit this should not be an issue.

John

[sleonard]

Originally Posted by Narflex

There's been a property added to the next build which allows you to force a capture device to use a specific video path.

So you can use UNC paths for this and it will allow multiple drives on an encoding server.

The client will currently stream directly from the encoding server if it's file path is accessible from the client itself (by using UNC paths or mapped drives) and what's being watched is not currently being recorded.

Written a few minutes ago in another thread. So currently, files are streamed directly from the server that stores them (provided it is a Sage network encoder) and soon we will be able to force each slave server/network encoder to record only locally.

I would ditch the central file server and have each Sage server/network encoder record only to its local drives. This would distribute the load among the various servers with none being hit too hard (unless, as jptaz said, you have everyone trying to watch the same recording at the same time)

brolling, I don't see any other limitations at all. I'd love to see this monster system in action.

[brolling]

So what all of you are saying is that A)the clients don't need to stream the data through sagetv server, and B)the recorders can be assigned storage paths individually.
If I'm understanding you correctly, this means that we could have three storage servers, each with ten capture cards pointing at them. The only system that cannot be duplicated to increasee speed is the sagetv server, which never has to see a byte of video if everything is set up correctly. The distributed recorders could save video files onto an array of file servers which the clients access directly per instructions from the server.

I've got to say, SageTV was designed right. If we build this system, which is reasonably likely, I'll share all of my configuration delights with you.
BRolling

[jptaz]

Actually more importantly Narflex is saying that is how it works.
FYI he is the software developer / Chief architect of SageTV.

So if he is saying that is how it works / will work then it will.

I have been using SageTV since version 1.2 and have to say that Frey is not perfect, but they have made a very scalable solution.

John

[sleonard]

Originally Posted by brolling

So what all of you are saying is that A)the clients don't need to stream the data through sagetv server, and B)the recorders can be assigned storage paths individually.
If I'm understanding you correctly, this means that we could have three storage servers, each with ten capture cards pointing at them. The only system that cannot be duplicated to increasee speed is the sagetv server, which never has to see a byte of video if everything is set up correctly. The distributed recorders could save video files onto an array of file servers which the clients access directly per instructions from the server.

I've got to say, SageTV was designed right. If we build this system, which is reasonably likely, I'll share all of my configuration delights with you.
BRolling

Here's what I'm thinking. May or may not be exactly the same thing, I'm not quite sure.

Three servers each equipped w/ ten capture cards and each running the full version of Sage. Server A is the master and B and C are setup as network encoders for A. Each server is also directly connected to it's dedicated storage whether its local hardrives, a seperate RAID box connected via fibrechannel, iSCSI, etc. or even a seperate file server as long as each Sage server has it's own. SageServerA would record to FileServerA, SSB to FSB, and SSC to FSC. Clients would be set up to connect to SageServer A. If a client reqests a recording that was recorded on SSA it would be streamed from SSA who got it first from FSA. Nothing special. But if a client requests a recording made by SSB and stored on FSB, then a streaming connection is made directly between the client and SSB who gets the recording from FSB. Thus the load is neatly balanced across the number of servers you set up.

The differences I can see from your scenario is A) that there is no need for the fourth Sage Server that clients are set up to connect to, B) All three of the boxes that actually have the tuners need a full copy of Sage though 2 are setup as slaves to the first and C) the clients only connect to the boxes running SageServer. Intitially they only connect to the master and stay connected to it constantly but can make temporary streaming connections to any other Sage Server box as needed.

Best storage solution would be both directly connected and dedicated, local hard drive, local RAID array, seperate RAID box connected via Fibre channel, etc. The Sage server IS the File server. Next would be a seperate file server on the network but dedicated to the Sage server.

The streaming traffic follows this path: File Server >via file transfer> Sage Server >via streaming> Client.

How's that?

[Dekard]

Interesting config... I'm very curious what application would need such a huge system. You'd literally have to have 50 clients watching varied programing to max this out... But where else then a resort? Hotel? Bar? Mansion?