Startup parameters: what they are and when to touch them

Startup settings are the handful of options your server reads every single time it boots, and a wrong value there stops the server before it writes a single log line.

6 min read · Updated Oct 21, 2026 · By GuavaHost Team

Most settings live in a config file inside your server. A few do not, because the game needs them before it has even loaded: which version to run, which world folder to open, how much memory to claim. Those live in Startup settings on your server's Settings tab, and they are applied as the server is launched.

Where they are

1. Sign in at customer.guavahost.com, open My servers and click Manage on your server.
2. Open the Settings tab.
3. Find Startup settings. Each option is a field with a short description of what it does.
4. Change one value, click Save next to it, then restart the server with the Restart button at the top of the page.

Nothing takes effect until that restart. The server is already running with the old values, and they are only read again at launch.

You will also see a Set by GuavaHost section. Those are the values we look after for you, such as the things tied to your plan and your machine, and they are not yours to edit. If a guide ever tells you to change one of those, change it in the panel feature it belongs to instead: the port lives on your Ports & network page, as adding and managing extra ports explains, and the memory ceiling comes from your plan.

The startup command, in plain terms

Behind those fields is one long command that launches the game, with your values dropped into it. Think of the fields as blanks in a sentence. Put something nonsensical in a blank and the sentence stops making sense, which is why a bad startup value fails so early and so silently.

That explains the most confusing symptom in hosting: you press Start, the status flicks to Starting, then straight back to Offline, and the Console shows almost nothing. The game never got far enough to write a log. Nine times out of ten the cause is a startup value, not a broken server. Server exited with a code on start covers that exact failure.

What you will find, by game

The fields differ per game, because each game needs different things before it boots. The pattern is the same everywhere:

• A version or branch. Which build of the game to run. For Minecraft Java this is the server version and the server type (Paper, Fabric, Forge and so on), and there is a dedicated Version page under Minecraft tools that does the job more safely. See choosing your Minecraft version and Paper versus Purpur versus Spigot versus Fabric versus Forge.
• A world or save name. Which folder on disk the game should load. Point it at a folder that does not exist and most games will happily generate a brand new empty world, which is the single most alarming way to lose a save. Back up first; resetting a world or changing the seed explains how this is meant to be used.
• A map, seed or world size. On survival games such as Rust, these decide what the generated world looks like. Changing them generates a different world.
• A secondary port. Don't Starve Together is the clearest example: its caves shard listens on a Caves port set here.
• A build flag or launch option. Some games take extra arguments for beta branches, mod loaders or compatibility layers.

If a field has a dropdown, use the dropdown. The lists exist because those are the values that actually work.

When you genuinely need to change one

Reasonable reasons: moving to a new game version or server type when the dedicated page for your game does not cover it, switching to a different world folder you have uploaded (uploading a Minecraft world is the usual route), turning on something a guide for your game specifically tells you to, or putting a value back after a change stopped the server from starting.

Not reasonable:

• Typing a bigger memory number in because you want more RAM. Your memory ceiling comes from your plan, not from a field. Asking for more than the plan allows gets you a server that refuses to boot, or one the host stops for exceeding its limit. Change the plan instead: changing your server RAM takes a minute and is prorated.
• Pasting flags from a random forum post without knowing what each one does. Performance flags for Java are a real and useful thing, but they belong in the one place designed for them and they need to match your memory. Aikar's flags explained is the version to trust.
• Changing several fields at once. You will not know which one broke it.

A safe routine for changing one

1. Take a backup on the Backups page. If the change rewrites or regenerates a world, this is the only thing standing between you and starting over.
2. Write the current value down somewhere outside the panel. A note on your phone is enough. This is the step people skip and regret.
3. Stop the server.
4. Change exactly one field and click Save next to it.
5. Start the server and watch the Console tab as it boots.
6. If it starts, play for a few minutes and check the world is the one you expected.

If it does not start, put the old value back before you try anything else. A startup problem that is fixed by restoring the old value tells you everything you need to know.

Getting back to the default

There is no undo here, which is why step two matters. If you have lost the original value:

• Check your notes, your Discord messages, or a screenshot. People often have one without realising.
• Ask us. Our team is online 24/7 and can tell you the default for your game and version.
• As a last resort, Reinstall server on the Settings tab rebuilds the base install with its normal values. Depending on the game it can delete files, so take a backup first and read reinstalling your server before you press it.

How this relates to config files

Startup settings and config files overlap, and when they disagree, startup usually wins because it is applied later in the launch. Two consequences worth remembering:

• If you edit a setting in a file and the server ignores it, check whether the same setting exists in Startup settings.
• If a value in a file keeps reverting to something you did not choose, it is being written at launch. Change it in the panel, not the file.

Editing config files in the panel file manager covers the file side, and if a start fails in a way the console does describe, why your server says Starting or is stuck offline will get you to the cause.

Common questions

Can I give my server more RAM by changing a startup value?

No. The memory ceiling comes from your plan and is set for you, so a bigger number in a field either does nothing or stops the server from booting. Use Manage plan to change the amount, and the difference is prorated.

Why does my server stop instantly with nothing in the console?

That is the signature of a bad startup value. The game process was launched with something it could not accept and exited before it wrote a log. Put back whatever you changed last and try again.

Do I have to restart after changing a startup setting?

Yes. These values are only read as the server launches, so the running server keeps using the old ones until you restart it. Save the field first, then restart.

Will changing the world name delete my old world?

It does not delete anything, but it does stop loading it. The game opens the folder you named instead, and if that folder is empty it generates a fresh world. Your old folder is still on the Files tab, so point the setting back at it to return.

Still stuck? Jump into our Discord at discord.gg/GuavaHost and the team will help you out.

• panel
• startup
• settings
• configuration
• troubleshooting

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