Connections limits

Other platforms, generic questions.

Moderators: Moderator, Global Moderator

User avatar
lokito50
Newbie
Newbie
Posts: 9
Joined: Tue Jan 09, 2018 5:01 am

Re: Connections limits

Post by lokito50 » Tue Apr 23, 2019 4:06 am

[quote="Switeck"]
If you only use private trackers definitely disable DHT.
PEX you can leave enabled because it won't do any harm if private tracker torrents are properly marked as private torrents.
[/quote]
So I upped my speed to 250MBPS down and 20MBPS up. Can I change any of the settings? If so, which ones?
Thanks

Switeck
Forum addict
Forum addict
Posts: 1520
Joined: Sat Jul 06, 2013 10:04 pm

Re: Connections limits

Post by Switeck » Tue Apr 23, 2019 7:34 am

A lot of speed increases by ISPs tend to increase burst speeds but don't let you run those speeds for very long -- minutes to maybe an hour or 2 before congestion (contention with other users) probably occurs.

So how fast can you now upload and download at consistently? (This tends to be way lower than speed tests apps show!)

User avatar
lokito50
Newbie
Newbie
Posts: 9
Joined: Tue Jan 09, 2018 5:01 am

Re: Connections limits

Post by lokito50 » Tue Apr 23, 2019 1:11 pm

Download at 25-30 MiB/s. Upload varies, it goes up and down, sometimes up to 1.8MiB/s. But most of the time it hangs around in the hundreds, oscillating to below 100KiB/s now and then.

Switeck
Forum addict
Forum addict
Posts: 1520
Joined: Sat Jul 06, 2013 10:04 pm

Re: Connections limits

Post by Switeck » Wed Apr 24, 2019 2:35 am

Increase the max upload speed to 1500 KiB/sec and test some more.

Also increase global max upload slots to about 75-150.
Max active torrents (though I don't recommend using torrent queueing) can be about 25-35.

Keep everything else the same.

Conscious_Fold
Newbie
Newbie
Posts: 5
Joined: Wed Apr 24, 2019 7:48 pm

Re: Connections limits

Post by Conscious_Fold » Wed Apr 24, 2019 8:12 pm

I have a 300/40 line. Downloading at max especially if the number of torrents is larger already sees a massive benefit of using a ssd for unfinished torrents. No you wont wear out your ssd any time soon. One of the hw review sites ran a benchmark last year and even a 500GB samsung evo 840 with 2d tlc flash (basically the worst regarding endurance) started showing some relocated sectors only after 300 TB of writes, and died around 600 TB. If you have anything more modern and larger with 3d tlc (vnand) like an 1tb evo 860 it'll last at least 3 to 4 times more, and the very best ssds will reach 9PB or more. It's a total non issue. Especially with current ssd prices making them so affordable. Also if you are using a cow filesystem (btrfs/zfs) turn off cow for the unfinished torrents folder. Finally since you probably can't afford a few 4TB ssds in raid10 you can use dm-cache to set up a ssd as a front cache for your hdd(s). That way the most commonly used data will be in memory, second most common on the ssd and the rest on hdd(s).

Switeck
Forum addict
Forum addict
Posts: 1520
Joined: Sat Jul 06, 2013 10:04 pm

Re: Connections limits

Post by Switeck » Thu Apr 25, 2019 6:55 am

The SSD write amplification issue needs to be taken seriously, even if more modern SSDs can handle far more abuse than older ones can.
Larger SSDs can spread the pain around more and suffer less, at least as long as they're not nearly full.

While not directly about write amplification, file fragmentation is directly related:
"qBitorrent horribly fragmenting my drive."    https://www.reddit.com/r/qBittorrent/co ... _possible/
"It's an 8TB drive, and after downloading ~2TB in torrents, I had almost 3 million fragments. I'm in the process of defragging the drive right now but it is taking absolutely forever (multiple days), with read/write speeds around 15-20MB/s."
"I only had maybe 50 files, and almost 3 million fragments. Really slows down read speeds."

While that was on a HDD, even SSDs will experience similar fragmentation which vastly increases write amplification.
So at its worst on a smaller+nearly full SSD, downloading 10 GB of torrents might cause 1 TB of writes on that SSD. (1:100 write amplification)

User avatar
Peter
Administrator
Administrator
Posts: 1638
Joined: Wed Jul 07, 2010 6:14 pm

Re: Connections limits

Post by Peter » Thu Apr 25, 2019 8:01 am

SSD life expectancy is a meme.

I mean.
IF you buy a NEW SSD, with bad TLC NAND (read, the cheapest of the cheapest SSD)... then yea, you should worry. Hell, it will die from normal use.
A regular, like Samsung TLC? It has enough write cycles to support your torrenting habits for years to come.
MLC? Any brand? Your grandchildren will download on your SSDs.

I bought 2pcs of El Cheapo Kingston MLC SSDs during a huge discount. Had them in RAID0, without TRIM.
Used them for YEARS. Like 5 years. Result? Bit of a slow down. What did I do? Dismount array, run trim.
Result? 100% factory speeds. They have been without RAID for 3 or so years again now... but, in daily use. For torrent, for development, virtualization, games, everything you can think of.

99% life left. NINETY NINE.
SSD. Will. Outlive. You. *

* Unless you bought some junk from the 2000s that has a buggy firmware, and you never took a minute to update the firmware.
Or you bought a junk TLC in 2019.
- qBittorrent team - server and forum administrator.
- Hungarian translation reviewer/moderator (+ translator).

Join the official qBittorrent Discord!
https://discord.gg/ma66Vv4

delmiss
Newbie
Newbie
Posts: 6
Joined: Sun Sep 29, 2019 10:13 am

Re: Connections limits

Post by delmiss » Sun Sep 29, 2019 10:15 am

Then the 10 megabits/second upload bandwidth is the big limiting factor.
Raw speed, that's 1.25 MEGABYTES/SECOND. TCP/IP networking and BitTorrent protocol overheads can reduce that to closer to 1 MEGABYTE/SECOND...or about 1000 KiloBYTES/second upload max in qBitTorrent.
Depending on how stable the connection is and how much over-provisioning your ISP does as well as contention ratio (and they're extremely unlikely to tell you how much they do of either) can change how closely you can get to the speed limits before everything downloading or uploading bursts close to max and then falls almost to 0.

Post Reply