2X HDHomerun and network usage

[dlandrum]

I am running Sage with two pci SD tuners and two HDHomeruns (four HD tuners).
My server uses five SATA drives dedicated to Sage.

I have two gigabit switches:
1) Sage server, HD homerun, hd homerun, link to router, link to other gigabit switch
2) 6 drops in my house, link to other gigabit switch

When I am recording more than 4 shows, the shows get recorded with some jerkiness ... especially if I am also watching another show via a drop in the house.

I have done everything I can to make the server fast and the drives fast. I see no cpu or memory issues.


Here is my proposed solution:
The server has a 100mb connection on the board. I have added a 1gb connection via PCI.

What if I use the 100mb connection to link the server to the switch with the house drops. .. and use the 1gb connection to the HDHR switch?

I could hardcode the clients to use the 100mb IP address. I could block Sage_HDHomerun from the 100mb card via firewall.

I would need to connect the "house" switch to the router too.

Anyone think this would help?

[jquinlan]

This is allot of data, don’t know if it would be the network or the drives is where the slowdown is at.
For the HDHomerun's, I would definitely separate them on their own network. The firewall process may work but its software. If you physically separate the tuners from the internal home network that may help.
Another thing may be to have each HDHomerun use a crossover cable directly to the PC via 1Gig cards, this way each tuner has full passage to the server.
The next thing would be the storage on the server. can you separate each tuner stream to a separate drive? Can the disk I/O handle the amount of data coming in, and then server out more recording to your clients.
What about using a network encoder, a second server to handle half the tuners to take the disk I/O load off them main server. But can the storage be shared between them while browsing recording and videos?

You definitely have a highend DVR System, I hope you can work this out and that SAGE is flexable enough to support it.

[NEOSG]

Have you tried giving each tuner it's own dedicated recording drive on the server? I can record 5 things at a time, and watch stuff, without problems, but I have drives dedicated to each tuner.

I realize that your using network tuners, and that I can't replicate in my setup, sorry

[dgschoel]

From the HDHR documentation it looks like the unit only has a 100mb port. If that is the case using a gigabit switch would seem to be overkill.

Question: How can I set it up so that each tuner (encoder) writes to a different drive? The only options I see for recording locations in Sage are based on space available rules. I would love to force each encoder to a different drive if it is possible.

[GollyJer]

Yeah, after testing my RAID5 setup it became evident that it couldn't keep up with syncronous I/O requests when multiple HD tuners were recording and we are watching a program. My guess is your having the same issue. Changing to a JBOD setup with recordings being spread across different drives fixed the problem.

[GKusnick]

Before changing anything, you might want to collect more data on exactly where the bottlenecks are. WinXP's Task Manager has a Networking tab you can use to get a rough idea of network utilization. More detailed stats can be had by using XP's performance counters to monitor disk reads/writes, network packets in/out, etc. You can also try using Ixia Qcheck or some similar tool to measure actual network throughput under various loads. If nothing else these tools will give you a way of quantifying the effects of any change you make.

[paulbeers]

Originally Posted by dgschoel

From the HDHR documentation it looks like the unit only has a 100mb port. If that is the case using a gigabit switch would seem to be overkill.

Question: How can I set it up so that each tuner (encoder) writes to a different drive? The only options I see for recording locations in Sage are based on space available rules. I would love to force each encoder to a different drive if it is possible.

Yes the HDHR does only have a 100mb port, but he is running two. That equals out to over 80mb/s which would severly limit any bandwidth for playback if he was capturing from all 4 tuners at once. I think in his case that GB is the way to go.

[korben_dallas]

Another option would be to add an additional dual-port PCI network card to the server, and then use crossover cables to connect the HomeRun's directly to the server.

[ToxMox]

Two HDHR devices should run fine on one 100MBit port or switch. The devices are 100Mbit but when you are recording two channels at once it is maybe around 30-40 MBit for the whole device. I'm guessing your bottleneck is the drives. Chances are you have more free space available on one drive versus other drives and all the shows are recording at the same time to the same drive. Setup each HDHR tuner to record to seperate drives and you'll probably be fine. That is what I did and I'm running two HDHRs and 6 SD tuners in the same system. The HDHRs I am running on a gigabit router to the 2nd NIC on my server so they are on their own little network.

[pat_smith1969]

Originally Posted by GKusnick

Before changing anything, you might want to collect more data on exactly where the bottlenecks are. WinXP's Task Manager has a Networking tab you can use to get a rough idea of network utilization. More detailed stats can be had by using XP's performance counters to monitor disk reads/writes, network packets in/out, etc. You can also try using Ixia Qcheck or some similar tool to measure actual network throughput under various loads. If nothing else these tools will give you a way of quantifying the effects of any change you make.

I have to agree with GK... before spending any money enable the disk counters in XP and see for certain if the drives are dogging down, is there excessive paging? is the memory buffer filling up?

My GUESS would be that the link from the one switch (100 meg) to the switch with the server on it is the bottle neck. If this is the case the PC wont see any network issues either because the bottle neck is elsewhere on the network. IF it is not a disk issue then I would go for the dual 100 meg NICS installed directly in the server (one for each HDHomerun). But I am just guessing on that.
Alternately you might see a large improvement moving to a single 10/100/1000 switch, one with enough ports for your needs. My reasoning is that cheap home quality switches dont keep a reliable ARP table. If a mac address is on a different switch, some low end switches will simply broadcast the traffic because it doesnt know the specific destination port. Other low end switches have a large amount of collisions and dropped packets. As a test you could just try the server on the same switch as the two HDHomeruns reducing the opportunity for broadcasts.

[spike5884]

Here is a very interesting network card that would take the network TOTALLY out of the picture as being an issue.

HP NC150T PCI 4-port 1000T Gigabit Combo Switch Adapter

[dlandrum]

Thanks for the tips. It seems the easiest solution was to map each HDHR to a drive. So I did that. I watched the disk write queues and did not see anything glaring as an issue.

I was thinking about writing an app to move files between the drives, but the Sage implementation of recording discovery seems poor.

Anyone had success at automating drive space balancing whilst Sage is loaded?

[Goodspike]

Originally Posted by korben_dallas

Another option would be to add an additional dual-port PCI network card to the server, and then use crossover cables to connect the HomeRun's directly to the server.

Not certain, but I don't think you need a crossover cable, because I don't think I have one. You do need a program like Magik DHCP.