FTB OceanBlock 2 Server: Requirements and Setup Guide

You want your group stranded on the same endless ocean, so you need an FTB OceanBlock 2 server instead of one person's singleplayer world. FTB does not hand out a zip of server files for this pack; you get a small installer that fetches the pack, Java and NeoForge. This guide lists the requirements as FTB's own API gives them on 3 November 2026, the install commands, how much memory to give the server, and the parts that surprise server owners: the lobby and team bases, chunk loading, and the backups the pack makes on its own.

Quick answer: FTB OceanBlock 2 server requirements: the latest release, pack version 1.21.1 (version ID 100482, published 24 August 2026), runs on Minecraft 1.21.1 with NeoForge 21.1.248 and Java 21. FTB lists at least 4 GB of RAM and recommends 6 GB, and its server installer sets a 6 GB Java heap (-Xmx6144M), so give the server about 8 GB in total to leave Java room outside the heap. On Linux, download serverinstall_128_100482 from FTB's server files page, keep that file name, make it executable, run it in an empty folder, accept the Minecraft EULA and start the server with ./run.sh. The installer downloads Java 21 itself.

FTB OceanBlock 2 Server Requirements

Checked in the FTB API and on the pack page on 3 November 2026:

The pack's version numbers look like Minecraft versions, and that trips people up. "1.21.1" here is the pack release; the one before it was pack version 1.21.0 from 21 August 2026. All 46 versions FTB lists, from 1.0.0 up to 1.21.1, run on Minecraft 1.21.1 with the same 4 GB minimum and 6 GB recommendation. When a player says they are "on 1.21.1", ask which pack version they mean.

FTB released OceanBlock 2 on 14 February 2025, and on 3 November 2026 its page counted more than 1.35 million installs. The 1.21.1 changelog fixes players being left in Adventure Mode after going through the Lobby Portal to start their team, a multiplayer bug, so install 1.21.1 rather than an older release.

How Much RAM an OceanBlock 2 Server Needs

FTB's figures are 4 GB minimum and 6 GB recommended. The installer turns the recommended figure into the heap: its source code shows that for a NeoForge pack it adds -Xmx plus the recommended value to user_jvm_args.txt when that file has no -Xmx line yet. For OceanBlock 2 that line is -Xmx6144M.

The heap is not the whole Java process. Java also needs memory outside -Xmx for the classes of 288 mods, its threads and native buffers. If your plan has exactly 6 GB and the heap is also 6 GB, the process can run past the plan's limit and be stopped. A total of 8 GB with the default 6 GB heap is a sensible start for a small group. If the group grows or builds large automation, raise the plan first and the heap second, and keep a margin of a couple of gigabytes between the two. The pack ships the spark profiler, so /spark health show --memory shows how full the heap really gets before you change anything.

Install the Server Files on Linux

FTB's server files page for OceanBlock 2 gives the download command for Intel and AMD machines. In full:

mkdir -p ~/oceanblock2 && cd ~/oceanblock2
curl -JLO "https://api.feed-the-beast.com/v1/modpacks/public/modpack/128/100482/server/linux"
chmod +x serverinstall_128_100482
./serverinstall_128_100482

On an ARM server, download from .../128/100482/server/arm/linux instead; the file name stays serverinstall_128_100482.

1. Start in an empty folder. The installer warns you when the folder holds other files and is not an earlier install of the same pack.
2. Keep the file name. FTB's server guide says the installer reads the pack and version from it; after a rename it asks you for the pack ID and version ID.
3. Answer the prompts. It shows the pack name, version and NeoForge 21.1.248, then asks whether to continue, whether to download Java and whether to run the mod loader installer. On a fresh machine, answer yes to all three. To skip the questions, add -auto, which the installer's README describes as "Doesn't ask questions, just runs the installer".

The installer's source shows what happens next. It downloads every pack file not marked client-only, so the 23 client mods such as Iris and Embeddium stay off the server. It unpacks Java 21 into a jre folder, runs the NeoForge installer, rewrites run.sh to use that Java with nogui, adds the -Xmx6144M line, and writes a .manifest.json that it reads again during updates. Leave that file where it is.

Now start the server once:

./run.sh

The first start stops right away and writes eula.txt. Read the Minecraft EULA, and only if you agree, set eula=true and start again:

sed -i 's/eula=false/eula=true/' eula.txt
./run.sh

On Windows, download the Windows installer from the same server files page, put the .exe in an empty folder, double-click it and start the server with run.bat, as FTB's guide describes. FTB does not offer the server as a zip: its guide explains that the installer lets FTB hotfix a release without shipping a new version.

Change the Memory Setting

Open user_jvm_args.txt and edit the -Xmx6144M line. With 12 GB available you could set -Xmx9G, for example, which keeps 3 GB outside the heap. FTB's memory guide shows -Xmx and -Xms on the last line of run.sh, an example from an older pack; if you find a heap setting in both files, keep it in one place. The guide also warns that on a hosting service the provider sets the memory, so a higher -Xmx does not give you more than the plan includes.

Running OceanBlock 2 on a Hosting Panel

A game panel usually gives no shell to run FTB's installer. Use the panel's modpack installer if it lists OceanBlock 2 (the pack has a CurseForge project), or run the installer on a Linux machine as shown above and upload the folder over SFTP with its structure intact. Select Java 21 in the startup settings, and ask the host how its startup handles a NeoForge server with run.sh and user_jvm_args.txt instead of guessing a jar name.

On our modpack hosting, the panel's modpack installer sets up the CurseForge and Modrinth packs it lists, NeoForge is one of the server types, and packs it does not list go up over SFTP. Ask in live chat whether OceanBlock 2 1.21.1 is in the installer before you order.

First Join: the Lobby and Team Bases

OceanBlock 2 manages multiplayer with FTB Team Bases, and FTB's Teams documentation names this pack as the example. New players spawn in a lobby. They go through the Lobby Portal to start their team and pick one of the starter bases, which FTB's pack page calls "prebuilt spawn islands". With Team Bases loaded, a team can only be created by creating a base. Friends who want to share one base should not each go through the portal. One player creates the base, invites the others through FTB Teams, and they join that team.

The pack's own ftbteambases-server.snbt in version 1.21.1 sets a few things you should know:

• Bases sit 4 regions apart, which is 2,048 blocks of clear space between the edges of two neighbouring bases, and no base is placed inside the 8,000-block square around the world centre, where the lobby is.
• When a player creates a base or joins an existing team, the pack sets an FTB Essentials home named "home". The pack allows one home per player, so /home takes them back to their base. /ftbteambases home needs permission level 2 in this pack.
• Leaving a team clears that player's inventory (clear_player_inv_on_leave: true). Tell your players before someone switches teams with a full inventory.
• A disbanded team's base is archived, not deleted. /ftbteambases archive list shows archives and /ftbteambases archive restore <archive-id> brings one back. A purge deletes for good at the next restart.

As an operator, /ftbteambases list shows every base and /ftbteambases visit <base-id> teleports you to one.

Chunk Loading and Claims

The pack's FTB Chunks world config allows 500 claimed chunks and 25 force-loaded chunks per player. Its force_load_mode is "default": force-loaded chunks only stay loaded while nobody from the team is online if a team member has the ftbchunks.chunk_load_offline permission in FTB Ranks, so without it a team's machines stop when they log off. "always" allows force-loading with nobody online, which costs CPU all night; "never" requires an online team member.

To change it, open the map (M by default) as an operator and use the purple gear at the bottom right, which edits the server config. To edit the file instead, copy ftbchunks-world.snbt to world/serverconfig/ftbchunks-world.snbt and change it there. FTB's documentation suggests that copy because the files in config can be overwritten on modpack updates.

Backups the Pack Makes by Itself

OceanBlock 2 ships FTB Backups 2, and its config/ftbbackups2.json turns automatic backups on. Every 30 minutes (0 */30 * * * ?), if a player has been online since the last backup, it writes a ZIP to the backups folder in the server directory and keeps the newest 5. It skips a backup that would leave less than 500 MB of free disk. Operators at permission level 3 can run /backup start for a backup now, or /backup snapshot for one that the 5-backup limit never removes.

To restore, FTB's documentation says to stop the server, rename the current world folder (for example to world_old), extract the ZIP you want from backups, copy its world folder into the server directory, rename it to world and start again. These ZIPs live on the same disk as the server, so copy one somewhere else before an update.

Update to a Newer OceanBlock 2 Release

1. Read the new version's changelog on the pack page.
2. Stop the server and copy the whole folder, including world, config and .manifest.json, to another location.
3. Download the new version's installer into the same folder (the version ID in the URL and file name changes) and run it. The installer reads .manifest.json, recognises the same pack, shows "Is Update: true" with the number of unchanged, changed and removed files, and downloads only what changed.
4. Check your config changes afterwards. The pack's manifest, which the installer updates from, covers folders such as config, mods and kubejs but not world, so settings kept in world/serverconfig stay as they are.
5. Have every player update to the same pack version before they join.

The StoneBlock 4 setup guide uses the same installer, and the FTB modpacks hosting guide covers other FTB packs.

Check the Server Before Inviting Everyone

Run /spark tps for the tick rate and /spark health show --memory for memory use. Join with the same pack version from the FTB App, go through the lobby portal and create a test base. Run /backup start once and check that a ZIP appears in backups.

FAQ

What are the FTB OceanBlock 2 server requirements? Pack version 1.21.1 needs Minecraft 1.21.1, NeoForge 21.1.248 and Java 21. FTB lists at least 4 GB of RAM and recommends 6 GB; plan about 8 GB in total so Java has room outside the 6 GB heap the installer sets.

Do I need to install Java for an OceanBlock 2 server? Not with FTB's installer: it downloads Java 21 into a jre folder in the server directory. On a hosting panel, choose a Java 21 image in the startup settings. Our Java version guide explains why Minecraft 1.21.1 needs Java 21.

Where do I download the OceanBlock 2 server files? From FTB's server files page for the pack: choose your operating system and version 1.21.1 (ID 100482). FTB offers no server zip: the installer downloads the pack files, NeoForge and Java for you.

Can OceanBlock 2 run on Minecraft 1.21.4 or a newer version? No. Every OceanBlock 2 release FTB lists targets Minecraft 1.21.1 on NeoForge, and clients must run the same pack version as the server.

Will OceanBlock 2 run with 4 GB of RAM? 4 GB is FTB's minimum. FTB's memory guide says to lower both -Xmx and -Xms when you reduce memory, so set -Xmx4096M and leave no higher -Xms value behind. Expect less headroom as bases and automation grow.

How do my friends and I play on one base? One player goes through the lobby portal and creates the base, then invites the others through FTB Teams. Once they join that team, /home takes each of them to the shared base.

Sources

All opened on 3 November 2026:

• Feed The Beast: FTB OceanBlock 2 pack page (requirements, installs, release date, pack and version IDs), OceanBlock 2 server files for Linux
• FTB API: pack 128 (46 versions, specs), version 100482 manifest (targets, file list, client-only flags, pack configs config/ftbteambases-server.snbt, config/ftbbackups2.json, defaultconfigs/ftbchunks/ftbchunks-world.snbt, defaultconfigs/ftbessentials-server.snbt), 1.21.1 changelog
• FTB Docs: Create your own server, Memory allocation, Team Bases, Team Bases commands, Team Bases configuration, Teams, Chunks configuring, Backups 2, Backups 2 configuring
• FTB Server Installer on GitHub: README, main.go, modloaders/neoforge.go, repos/ftb.go, release v1.0.53 (21 October 2026)
• spark: Command usage
• Minecraft: End User License Agreement