Hard Drive bottle neck or something else

Channels DVR Server
#1

I've been running channels for about a month in prep for dumping D. One issue I've been dealing with is problems with playback while recording a few shows. I'm using a new SD 4K tuner feeding a moderate quality system and saving to an older 500g hard drive I had laying around. If things work our I'll opt for a new 4T drive for storage.

I'm getting a very choppy playback when I tune in after a show has started and opt for watch recording. I'm using a Tivo stream 4k mainly and my FS4k is pretty much unusable for playback. Not sure where the issue lies, the hard drive is my suspicion.. What is a good drive to use. I know my older HR2x dvrs use cheap slow drives but they are optimized for that.

#2

There are a lot of places for a bottleneck to happen. 1st, can you watch the SD live with no chop? If not, the OTA or the network is the problem.

Next look at the network. If you are using WiFi, try hard wired. Put the SD, the server, and the TV all in one place. You can get a hard wire adapter that will work on the Tivo or the FS4K at Amazon for $15. If you can't do hard wired, at least try to get everything close to the router.

I gather from your post you are using an external hard drive. For testing purposes, you can try using you machine's internal drive.

If you server lets you monitor CPU, Disk, and Network, run the monitor and see if anything is maxed out.

#3

Thanks for the quick reply. Live isn't the issue- everything plays fine live- problems arise playing recorded content. The only issue I have with live is the buffer, but I gather that is on the client end.

I am using an internal drive, just an older one. This morning is a good example of my issues. I typically tune is late to a show so I can skip commercials. I tuned into a show 18 minutes late opted for watch recording not live. Had a lot of glitches in the video at first but that resolved. However at the 18 minute mark the playback froze. Recording time continued to go on but stopping and starting I could not get it past the 18 minute mark. Gave up and switched to my D dvr.

Not sure what the issues are, really want this to work. It's not like I am inexperienced in any aspect of this but I need a rock solid dvr for other family members. Been also playing with a Tivo Bolt I picked up for $20 and other than needing some Mini's it's looking attractive. Want to drop D by end of month so I need to massage the issues.

1 Like
#4

If you can watch live while still going through the Channels server, that would rule out any networking problems, so you are left with CPU or Hard Disk issues.

I too always delay watch almost everything, especially the news. The only lingering problem I have is that once in a while a playback just freezes. All I have to do to recover is to exit back to the Channels list of recordings and restart the one I was watching. Although it only takes a few seconds to do this, it is still annoying.

#5

@matt832

What hardware are you using for your server? what OS?

What are you using to view the recorded content?

Do you have a wired gigabit network between the DVR server and the client?

#6

It would also be helpful to see if you have any errors in the DVR web ui log at the time of the issue.

#7

Here is the system spec's

OS
linux linuxmint
20.1 (kernel: 5.4.0-66-generic)
CPU
4 cores / AMD A10-7700K Radeon R7, 10 Compute Cores 4C+6G
load averages: 1.17 0.97 0.95
RAM
14.60 GB
38.4% free

Things seem to be settling down. Today I was able to tune in 15 minutes late and the whole recording played. without issue.
One thing I need to try is to load up the system with 4 shows recording at the same time and see how stable it is. A few days ago that is when problems arose. That lead me to questioning the hard drive. It's a Seagate 7200 rpm 500G drive. I know that most if not all DRVs use a 5400 rpm drive, Does anyone have suggestions on a larger drive? What spec. is most important in this applications?

#8

A basic hard drive should work fine, the IO requirements aren’t particularly heavy. It may be worth getting a hard disk made for NAS use as they are designed to run 24x7

#9

Regarding the choppy playback, are you running ComSkip? If so, try turning that off and see if that helps when trying to view a show shortly after it ends.

Also, test the network speed to your client to make sure it is adequate, the higher the better.

#10

I just recently set up my channels DVR which has been awesome - but i have also noticed that while watching a show that is currently being recorder, it tends to be a little choppy. just enough to make the wife notice and complain about it.

I used the speed test mentioned in the channels FAQ (never knew that was available). I got the following results:
Download: 190.71 Mbit/s
Latency: 6.40 ms
Jitter: 1.73 ms

Is that within the acceptable range? what SHOULD those numbers be?

It is connected via wifi to an eero router. The server is running on an unraid docker and is connected via gigabit ethernet.

also - i tried watching a show while it was being recorded and watched my resources on the channels DVR server and there was not really any noticeable spike us CPU or memory usage. So I am thinking the bottleneck in my case might not be the server but the network or the hard drives?

#11

I'd be a fan of having active recordings go to the faster internal storage for a certain amount of time while delayed watching or comskip or whatever, and be moved to a different location after the whatever amount of time has expired. 24 hours maybe. Enough time for people to watch it and / or have it comskipped faster then moved somewhere else. I understand this wouldn't apply to a nas and there are ways to set this up on my own, but a feature in the ui would be cool.

#12

We would need to know your setup, hardware, etc. The speed test is kinda sorta poor but not so poor it would be unplayable I would think. My hard connected shield will usually be around a gigabit in the speed test if nothing is happening on any clients. My chromecast just pulled a measly 83.21, 4.07, 10.04 while streaming on the shield. No issues with the recordings here, just fired one up. It was a completed recording, not actively recording. Sounding like storage speed issue.

#13

so dumb question but that speedtest for the apple tv (http://x.x.x.x:57000/speedtest where x.x.x.x is the ip of the apple tv.) that is testing the speed to the internet or the speed between the channels dvr server and the apple tv device?

#14

The local connection speed between the two devices. The apple tv and the dvr server. Doesn't really sound like your network is the issue, we'd need to know your setup to keep troubleshooting, but sounds like I/O speed issues.

#15

ok great - i thought that was the case - thanks for confirming. handy tool!

so when i experience the issue, it is definitely not unwatchable - it stutters just enough to be annoying. like it will stutter a little once ever 3-5 minutes. and its just video jump - like it skips a few frames - the audio stays intact. so its watchable - but annoying.

sounds like network could be playing a role. Unfortunately I cant easily get a hard wire to that location, so I have to rely on wifi.

as for hardware - the device is an apple tv 4, and the server is admittedly super old:
CPU: Intel® Core™2 Quad CPU Q9550 @ 2.83GHz
Memory: 2 GiB SDRAM

running in a docker on an unraid server.

it has a variety of hard drives some older and some new WD Red NAS drives,

#16

I'm just gonna be point blank with my answer here, but let me start by saying that I'm no apple expert, or nas expert, or a docker expert, but that is quite a bit of subpar equipment connected up to some maybe older drives, over wifi for that client, and the network speeds should be sufficient, but this specific use case, I think your right. The network. A hard connection would definitely solve it.
But since that isn't possible, we're just gonna have to solve it a different way. Do you at least have a long enough patch cable to test the theory or temporarily relocate the apple tv to see?

#17

haha - yea totally agree - my unraid server has been in service for many years and has been limping along - i know it is way overdue for an upgrade. honestly i have been shocked how much service i have been able to squeeze out of that old unraid server.

So I don't have a super long patch cable but thats a good call about moving the apple tv. I will temporarily move it into my office where i an easily connect it to an ethernet jack and see if that solves it. If that does the trick then at least i know the issue.

Thanks!!

#18

Ok, great. If that solves it then possibly you could use a moca adapter to hardconnect it in the other room.

#19

so this is weird - after moving the apple tv into my office and connecting it to an ethernet cable, when i run the speedtest I get 95.41 Mbit/s.

I tried using two different ethernet cable to rule out an issue with the cable. I would have expected much higher speeds on the hard wire.

#20

Did you disconnect it from the wifi first?