Streaming itune movies stutters

To offload some space I am moving itunes movies to a share on my 5N. For the most part the stream goes well and then I get a stutter and pauses - then fine for a bit. I have tried a direct connect to my laptop and this seems much better - maybe one pause. But once back on the normal network and anything else touches the 5N I get pauses.
My 5N has 4 3TB WD reds and a 64GB M4 msata. On a 1Gig connection and when using “disk speed test” app I get 80-100MBs writes and 40-90MBs reads.
Its the reads that worry me - since playing a movie is just a slow read over a long time.
Latest firmware on both dashboard and drobo.

Anyone else have this problem? I can copy a 2G file in a min or two, but I cant play a 2G file slowly over a 90 minute movie timespan.

For streaming it’s all about latency and minimum sustained transfer speed. A slow constant flow is better than large bursts followed by silence.

What kinds of bitrates are you trying to stream?

Also, what switch/router are you connected to?

Not sure how to tell what bitrate itunes is wanting or trying to use.

The 8-port GigE routers/switches that I’m using are old but I think are ok - they are SMC EZ Switch 8508T 10/100/1000[hr]
Found a little more info on the bitrate for the file/movie I was testing with. An old John Wayne movie Hatari and info in itunes says: MPEG-4, 1.79GB, bit rate 115 kbps, profile - low comp, encoded with handbarke, total bit rate 1579 kbps

Streaming the file now without problems - now kicking off a speed test at the same time and just got 87.7 MB/s write and 100.2 MB/s read - with no skips or jitters. Then kicked off a TM backup to the 5N and today still no pauses or jitters.
I did take the 5N back downstairs and so it is connected to one SMC switch that is cabled to another switch in my study.

Ok - first pause seen after playing about 5 minutes of video - but nothing like last night.

Thanks for any suggestions and I’ll keep reading and trying things. If just itunes would allow for a larger stream buffer like in the old days this would be a non-issue

If your 5N was recently set up, Drobo takes a a day or two to “optimize” the array, so that might have been the source of your slowdown.

The array had been setup since 3/28 and then an additional 3tb drive put in on 4/1 and then the 64G msata card put in on 4/5. Does the Hot Data Cache need a few days to learn about your usage?

I had also been adding data to the array for the first week fairly heavily - getting backups and data moved over.

I’ll let it sit for a few days and update with another streaming try or two to see if the jitters are gone.



Copied a movie over the 5N and then imported it into itunes. Movie still stutters from time to time. Then played a movie that had been copied over to the 5N more than a week ago - just to make sure some internal house keeping was not needed and it also stuttered.

To test this again I copied a mounted my movie share on my macbook and imported into itunes - this time no skips or stutters or anything. Started the same movie back up on my imac and stutter stutter stutter.

Both are wired and connected at 1000baseT. I’ll start checking network settings, but any suggestions anyone has would be much help.

Just curious, where is your iTunes database/library stored?

I have most itunes data on a firewire attached drive, but also offload some movies and tv shows as space is needed to either another internal drive or the drobo. I use the ‘alt’-drag method of importing so as to keep their location and not move to the itunes official folder.

I have been trying all kinds of things - seems to have gotten a little better. I unplugged my old drobo 2nd gen as it now has started to throw lots of errors in the system log and I did a safe boot which seems to have cleared up some strange sandboxd errors.

I also copied a movie to my DroboFS and it was able to stream without any jitters as far as I could tell.

Odd, but at least it sounds like things are getting better.

Your switch looks OK (it has full switching fabric, so it’s not a faux Gigabit switch). If you have Jumbo frames enabled, it might be worth turning it off as a test.

Just to be certain, the link between the upstairs and downstairs switch reports Gigabit?

The good news is that using BlackMagic disk speed test, I am getting anywhere from 80-95MB/s writes and 90-103 MB/s reads.
Saw it top out at 107.1MB/s read. So with these speeds it appears that the switch and cables are ok. BTW - I did have some old cat5 cables and I replaced them with nice short ones from Monoprice - Cat6.
The switch links are reporting Gige - Drobo5N to an 8-port SMC GigE and then to another SMC 8-port GigE and then to my laptop or imac.

Thanks for the suggestion - something will spark a cure here.

I did notice that the Hot Data Cache went to 2% good this afternoon and then back to 100% good after a bit. Its sitting at Good (Life 100%) right now.

Maybe I’ll try a dont spin down test and see what happens. If this thing has any kinda read-ahead - it would just cache the 1 or 2GB movie file and life would be good.

[quote=“stumantexas, post:10, topic:66150”]
The good news is that using BlackMagic disk speed test, I am getting anywhere from 80-95MB/s writes and 90-103 MB/s reads.[/quote]

So it looks like you have great base performance from your 5N, like most of us who have got one :slight_smile:

[quote=“stumantexas, post:10, topic:66150”]
I did notice that the Hot Data Cache went to 2% good this afternoon and then back to 100% good after a bit. Its sitting at Good (Life 100%) right now.[/quote]

Hmmm… you’re not the only one who has reported this… [thinking]

How about this for a test - take out the mSATA and see if the stuttering remains. If you have repeated requests for a file, then it will at some point trigger that file to be raised to the Hot Data Cache. If the logic involved in that is even slightly off, that could well result in the file being up-tiered at the same time as you’re trying to watch it. If my [cunning and rather baseless theory] is right, that may be causing the issues.

Taking the msata out is a good test - i’ll try and run that in the next day or two. Watching Zombiland right now and
no skipping - even kicked off a TM backup to the 5N and maybe a split second skip but hard to tell. I have rebooted and
turned off wake-on-lan and gone into safe mode once. I did turn off drive spin down as well.

I know - troubleshooting 101 - never shotgun fixes, but it was late and I was having fun.

More info to come.


Any resolution to the slow reads / stuttering during streaming?

I have almost the exact configuration as you…I have an enormous number of files on this
drive, which are painfully slow to access. I can copy a 1.2gb file to it in 15 seconds. But
just trying to open a folder with 490 photos in it takes 21 seconds just to populate a file list.


i have not solved this problem. I can watch a movie and only stutter once or twice and then watch another movie and its almost not watchable.
I have done so many things that I dont know if anything made any difference.

I am one of those people that use virus scans on a mac - I know, dont make fun of me. I turned off the active scan for this share and will see if that helps or not.

Something else is definitely awry. I had a 4.7TB iTunes library on my old Drobo v2 connected via FW800 and it never stuttered to the AppleTV’s, laptop or desktop. (I use the aTV 3 preset in Handbrake, so my files are about 5100kbps on average)

I assume you have iTunes running on a Mac/PC that is pointing to a spot on the 5N as your library?

I would troubleshoot iTunes if you are getting good speeds out of the 5N with other apps.

Create a new iTunes library with just a few test movies on the drive local to the machine running iTunes and see if they stutter when delivered across the network.

It might also be worth noting that iTunes doesn’t ‘stream’ to clients in the traditional sense. Movies/TV Shows are played directly from the source. No buffering or trans-coding.

Any update on this guy’s situation, or similar situations of others? I’m currently utilizing a brand-spankin’ new Drobo 5D for streaming iTunes to the various Apple TV’s and iOS devices in my home, but I’m starting to think that I might be better served by the 5N. I don’t actually have a need for the fast speeds on the host computer as it’s merely a headless Mac mini home sever that only exists for iTunes. I only went with the 5D because it was direct-attached and therefore officially supported by Apple for Time Machine… but that’s not working out either (see this thread if you’re interested) so now I just want the fastest and most reliable iTunes home sharing solution.

That said, I won’t tolerate any reliability jankiness whatsoever. The 5D currently pipes my massive (sometimes 20+ GB) blu-ray rips to my home’s Apple TV’s and iOS devices without breaking a sweat. I don’t want to mess with my setup if it’s going to be any less reliable. At the same time, the faster network transfer speeds of the 5N would be nice, as I could then use my Drobo for more than just iTunes. I currently only get about 25mb/s reads and 30mb/s writes when accessing the 5D over the network. With the 5N I could actually host my Aperture library and some other beefy files.

…but again, it would need to be reliable. Is the OP here just a one-off case, or is iTunes home sharing from a Drobo 5N going to be flaky for everyone? How does iTunes home sharing work, anyway? Surely it wouldn’t have to pipe the entire video file from the 5N to the Mac mini, then again the Mac mini to the Apple TV… right? I’m hoping that the Mac mini would simply do the “handshaking” and link the 5N up with the Apple TV. If that is the case, then it stands to reason that I should actually get better streaming performance from the 5N. I can’t seem to find any solid information about this though.

Bleh, so much unknown!

For the best reliability, I would stay with an actual Mac being the iTunes server.

Anything that runs on a NAS like the 5N relies on third-party solutions that don’t necessarily support Apple’s DRM and whatever changes they may decide to make in the future.

Running actual iTunes as the server will keep you from always being a few steps behind. Also, you can install any available server you need on the Mac, as well as transcode if necessary (with Plex, Orb, etc).

Plus, having the server side as a separate piece (computer) means you can upgrade the server for faster speed or bigger network pipe. On a standalone NAS, upgradeability is limited, if it exists at all.

You’re getting 25-30 MB/s, not mb (which would be 3.125-3.75 MB/sec), right?
Regardless, that sounds slow, unless your 5D has recently been set up and is still doing its internal optimization.
How is your 5D connected to your Mac mini?

AFAIK iTunes sharing is not a “hand off” of “Hey, go retrieve this directly from _____” to the client device like native Chromecast apps do. I don’t think the client device has knowledge of the physical location of the library, only what the sharing machine is exposing to it. I’d be happy to be told I’m wrong here though.

If I’m not incorrect above, using a 5N as the library location for the Mac mini would clog the communication pipe more than using a 5D. With a 5N, the Mac mini is accessing the iTunes library through the network connection and serving its iTunes clients through the same network connection.
With a 5D, the network connection is only being used for serving iTunes clients, accessing the iTunes library is through USB or Thunderbolt, so there’s more bandwidth available, and more importantly, more stable throughput on the network connection for the streaming.

Of course, if you have other uses for the 5N, as you’ve noted it might host your Aperture library, then it might make sense to go with the 5N and still use the Mac mini as the iTunes server, even though you might be clogging its network pipe.

With an iTunes-compatible server app running on a 5N, the communication is direct between the 5N and the client. However, you’re stuck with third-party solutions that tend to be “chasing” Apple anytime things change.

Yeah, I’m not interested in any third party solutions. And I did mean MB not mb (I honestly never realized that capitalization was how you set them apart).

Sounds like my best bet is to keep the 5D then. I have it connected via Thunderbolt. And yes, all of these tests have been done during the first week. Strangely enough, when my MacBook is connected via Ethernet I top out at exactly 11.2 MB/s for both read and write. The 25-30 MB/s is what I get on WiFi. Seems… odd.

Oh well. The most important thing is to be able to stream my movies. Thanks for the explanation.

Hehe, if you want to get really technical… (see footnote, as I tend to tangent too much)

Anyways, yes, if you want to stay 100% Apple-supported, stick with the 5D on your Mac mini.

I find your poorer wired performance puzzling too.

Perchance is there a 100 Mbps (Fast Ethernet) hub, switch or router in your wired chain?

If your wireless is 802.11n and your wired is going through a 100 Mbps segment, that would explain it.

Another possibility is if Thunderbolt and Ethernet are somehow sharing bandwidth, though TB should have more than enough bandwidth and shouldn’t be affecting even Gigabit Ethernet.

To confuse things even more, most removable storage didn’t transition to using decimal figures until DVD-Recordable, as CD-ROM still used binary figures.

Thanks. I’ve never actually tested network performance on that Ethernet jack before. I guess I’ll look into it. If I have a 100 Mbps botteneck then it’s either the Ethernet switch or my in-wall cabling. The scary thing is that I’m 100% positive I bought a Gigabit Ethernet switch. Hopefully I just set it up wrong or something… if it’s the in-wall CAT5e then me and my builder are gonna have issues.