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Comment by lprd | Hacker News Reader

Will the presentation be available online anywhere? This topic is very interesting to me as I maintain a Plex server for my family and have always been curious how Netflix does streaming at scale.

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There is a EuroBSDCon youtube channel. The last time I presented, it was a few weeks before the recordings were processed and posted to the channel. I'm not sure how soon they will be available this year.

I have to say that a lot of this may be overkill for plex. Do you know if plex even uses sendfile?

It's 100% overkill, haha! I was just asking because streaming architecture really interests me. I have two nodes (one is TrueNAS with ~50tb of storage), and the other is a compute machine (all SSDs) which consumes the files on the NAS and delivers the content. My biggest bottleneck right now is that my internal network isn't 10Gpbs, so I have to throttle some services so that users don't experience any buffering issues.

Truenas also introduced me to ZFS and I have been amazed by it so far! I haven't dug to deep into FreeBSD yet, but that's next on my list.

One thing to remember with ZFS is that it does not use the page cache; it uses ARC. This means that sendfile is not zero-copy with ZFS, and I think that async sendfile may not work at all. We use ZFS only for boot/root/logs and UFS for content.

Very interesting, I had no idea. Would adding something like an intel optane help performance for large transfers with a lot of I/O? I manage my services with a simple docker-compose file and establish the data link to my NAS via NFS, which I’m sure is adding another layer of complexity (I believe NFSv4 is asynchronous?).

Short answer: no

There's a lot of blogs that go over this in detail for our usecase at home. Your can do it but you will not see much improvements if any at all.

From the tail end of the presentation I'd expect UFS2 isn't a potential bottleneck (I'd naively expect it to be good at huge files, and the kernel to be good at sendfile(2).) Is that your opinion as well, or are there efficiency gains hiding inside the filesystem?

Hmm. While this represents a write-once-read-extremely-many (someone here mentioned how there's no FS cache (?) (https://news.ycombinator.com/item?id=28588682)) type of situation, I'm curious if bulk updates have brought any FS-specific Interestingness™ out of the woodwork in UFS?

(I'm also curious where the files are sourced from - EC2 would be horrendously expensiveish, but maybe you send to one CDN and then have it propagate the data further outwards (I'm guessing through a mesh topology).)

At some point the presentations will come up here https://www.youtube.com/c/EuroBSDcon

How large is your family?

Just the closest /16 and a few friends.

Haha, not large at all! I've just built a couple of servers and their main responsibility is content storage and then content serving (transcoding). My main bottleneck right now is that I don't have 10Gbps switches (both servers have dual 10Gbps intel NICs ready to go). I have to do some throttling so that users don't experience any buffering issues.

Have you tried using a crossover cable and static IPs to link the two servers directly?

FYI if using modern hardware then you might not need a specific cable to try this thanks to Auto MDI-X: https://en.wikipedia.org/wiki/Medium-dependent_interface#Aut...

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