Why Your Seedbox Is Slow, and How to Find the Real Cause

Slow is a symptom, not a diagnosis

Almost every "my seedbox is slow" ticket comes down to one of four things: you're measuring a single connection and calling it the whole pipe, you've spent your monthly bandwidth, a disk is busy, or one of your own apps is eating the box. The fifth case is that it really is us, and that one we fix.

Here's the order I work through, and how you can do most of it yourself in about ten minutes.

Step 1: measure the right thing

Before anything else, get a number you can compare. Two useful measurements:

• Our speed test runs against a real production server in the Netherlands, not a mirror set up to look good. It reports speed per thread and estimates what Plex quality your line can hold. Run it once during the day and once at night.
• A transfer you can repeat. Pull the same large file twice, once with one connection and once with several. If one connection gives you 8 MB/s and eight connections give you 60 MB/s, nothing is broken. That's how TCP works over distance.

What is not a measurement: the number on a pricing page. Every Bytesized appbox is on a 10 Gbit connection, and no shared seedbox anywhere gives one account 10 Gbit to itself. A port speed is the ceiling of the building, not the size of the room you rent. I wrote more about that on why a bigger Gbps number is not a faster seedbox.

Step 2: one connection is not the whole pipe

This is the single most common false alarm, and it isn't your fault: every FTP client defaults to one stream.

A single TCP connection between Europe and, say, Australia is capped by latency and packet loss long before it's capped by anything on our side. The fix is parallel transfers:

• In FileZilla, raise the number of simultaneous transfers in Settings, Transfers.
• With rclone, use --transfers 8 --checkers 16 on your copy.
• With lftp, pget -n 8 splits one file across eight connections.

If your throughput scales up with the number of connections, your box is fine and the limit was the path between you and it. Our guide on how to download files from your seedbox covers the tools.

Check your own line too. A 100 Mbit home connection is 12.5 MB/s at absolute best, and wifi at the far end of the house is often a quarter of that. Plug a laptop into the router and test again before you blame the server.

Step 3: have you spent your bandwidth?

Metered plans come with a monthly allowance: 3 TB on Appbox Lite at €5, 10 TB on Stream +3, up to 30 TB on the biggest boxes. Go past it and your traffic gets shaped for the rest of the cycle. Everything still works, it's just slower, and it feels exactly like the network breaking for no reason.

Your usage is on the panel. If you've run out and don't want to wait for the new month, boost it: €1.50 for another 0.5 TB, €2.50 for 1 TB, €4 for 1.5 TB, €7 for 3 TB. If you hit the ceiling most months, the +Stream plans are unmetered from €14 and cheaper than boosting twice.

Step 4: the disk, not the port

When the network checks out, it's usually storage. Seedboxes are bound by disk long before they're bound by the network, and a spinning disk shared by a few accounts has a hard limit on how many things it can read at once.

The pattern that bites hardest: several people, or several of your own apps, pulling large sequential reads off the same disk at the same time. Each stream on its own would be fast. Together they turn a sequential read into the disk head jumping between files, and everybody gets a fraction of what the disk can do. A disk in that state can deliver a couple of MB/s while its hardware is perfectly healthy.

You can't see this from inside your box, and that's fine, that's our job. What you can do is stop making it worse: don't run fourteen parallel SFTP sessions while a torrent client rechecks 2,000 torrents and Plex scans your library.

Step 5: your own apps

Things I find on a slow box that turn out to be the box's own workload:

• A torrent client rechecking a big library. After a restart, a client with thousands of torrents spends minutes reading every file back off the disk. The web UI looks empty or frozen while it does. Let it finish rather than restarting again, which starts the whole thing over.
• Plex transcoding more than the plan is sized for. Every plan line lists how many transcodes it's built for, from 2 on Appbox Lite up to 10 on the largest. Four people watching 4K while you download is not a network problem. A GPU Appbox from €25 handles the transcoding in hardware, and direct play handles it best of all. See 4K transcoding on a seedbox, GPU vs CPU.
• An rclone mount doing a full scan. Media servers scanning a cloud mount can generate a lot of small reads and a lot of API calls. Schedule scans, don't leave them on every change.
• A download client with no limits. Hundreds of active torrents with unlimited connections will fight your own streaming for the same disk.

Step 6: when it's us

Sometimes it is. Two honest examples of what we look for when a customer's numbers don't add up:

• A busy disk. We can see IO pressure per disk and attribute it per tenant. The fixes are real: change the IO scheduler on that spindle so many concurrent readers stop thrashing the head, or move the heavy account off it. I've seen that one change take a disk from under 2 MB/s aggregate to about 14 MB/s with the same people still reading.
• A host that's been up too long. Past roughly a hundred days, Linux hosts can develop a per-connection throughput collapse: the card is fine, the aggregate is fine, but each individual stream settles at a few Mbit. A reboot clears it, and hosts in that state get rebooted.

Neither of those is something you can diagnose from your account, so open a ticket. We've been running this since 2009 and we'd rather look than guess.

What to send us

A ticket with these four things gets a real answer on the first reply instead of a round of questions:

1. What you measured, with the number and the tool. "40 MB/s on eight rclone transfers, 6 MB/s on one" tells me more than "it's slow".
2. Whether it's everything or one app.
3. When it started, and whether it's constant or only at certain hours.
4. Your own connection speed from a wired test.

Which hosts actually deliver their advertised speed?

Honestly: no third party benchmarks this, so treat every claim, including ours, as something to verify rather than believe. What you can do is test before you commit. Our speed test is open to anyone with no account, most serious hosts have something similar, and a real result from your own line beats any number printed on a pricing page. If a host has nothing to test and only a big number to show you, that tells you something as well.

The short version

Test with more than one connection, check your bandwidth allowance, look at what your own apps are doing, then talk to us. Appboxes start at €5 a month for 500 GB on a 10 Gbit connection, and if the box really is the problem, that's ours to fix.