DayZ mods work reliably when mod folders, .bikey files, startup parameters, and client versions match exactly. This guide shows the controlled installation process and safe maintenance after updates. Create a backup before every change, add mods one by one, and after each restart confirm both the log startup and a real client join.
Why Mods Are So Important in DayZ
The DayZ Workshop offers everything from pure quality-of-life tweaks (map overlays, expanded base-building options) to complete total conversions with new weapons, vehicles, and loot tables. On your own server, you decide which mods shape your gameplay experience — this guide assumes the basic server setup from the first part of this series.
Back to: Setting Up a DayZ Server
Workshop Mods as @ModName Folders
Each DayZ Workshop mod is expected as its own folder with the @ prefix (for example @CommunityFramework). Upload the complete mod folder to your server’s main directory via the file manager in the panel — the mod’s folder structure must remain unchanged so the server can detect it correctly.
The keys/ Folder
So clients can connect to a modded server, the associated .bikey signature files must be located in your server’s keys/ folder. Each Workshop mod includes its own .bikey file(s), usually in the mod’s own keys subfolder. If a key is missing, the server refuses connections from clients with the installed mod — a common reason for “cannot connect” problems after a fresh mod installation.
CLIENT_MODS vs. SERVERMODS: The Key Difference
The DayZ egg distinguishes two types of mods through separate startup variables:
- CLIENT_MODS: Mods that must be installed both on the server and on every connecting client (such as new items, weapons, or map expansions that are visibly relevant to gameplay). They are loaded via the
-mod=startup parameter. - SERVERMODS: Mods that run exclusively server-side and remain invisible to clients (such as pure admin or anti-cheat frameworks). They are loaded via the
-serverMod=startup parameter.
If you accidentally enter a mod in the wrong variable, it either will not work at all (a SERVERMODS mod is missing client-side even though it would be needed there), or clients will be incorrectly asked to install a purely server-side mod. Both variables accept multiple mods, separated by semicolons, in the same order in which they should be loaded.
Overview of types.xml and the Loot Economy
Many popular DayZ mods (especially loot and economy mods) include their own types.xml or additions to it — this file controls which items spawn in the world, how often, where, and with what maximum quantity. Server operators who want to adjust the default loot distribution (for example more military gear or rarer vehicle parts) edit this file directly or use a corresponding economy mod as a base.
mpmissions — Your Server’s Mission Data
The mpmissions folder contains the actual mission data for your current map (such as Chernarus or a community map), including the types.xml mentioned above, spawn points, and map-specific configuration. When switching maps or making larger economy adjustments, this folder is the central place to start.
Persistence Wipe: storage_* Folders
The entire game world — placed buildings, stored items, vehicles, tents — is persisted in your server’s storage_* folders. A full wipe (for example at the start of a season or after a larger mod change that is no longer compatible with the storage format) means emptying or replacing these folders — this permanently deletes all player progress on the map. Announce a planned wipe to your community in good time and create a backup beforehand using the panel’s backup function.
Mod Updates After DayZ Patches
After every official DayZ update, Workshop mods may not have been updated yet. Combined with an enabled forceSameBuild setting (see part one), this causes clients with outdated mod versions to be refused connection. After every patch, first check whether your installed mods have already been updated before updating your own server — otherwise you create a gap where neither the old nor the new mod version matches the server.
Performance and Restarts
The more mods you use, especially economy and loot mods with many additional item definitions, the higher the server load. A regular scheduled restart (see the first part of this series) becomes even more important as the number of mods increases, so performance stays stable.
Official Sources and Installation Checks
Bohemia Interactive documents in the DayZ mod structure that Workshop mods typically contain addons, a keys folder, and .bikey files. The official server configuration describes -mod and -serverMod as separate startup parameters. After every change, check whether all expected mods appear in the startup log and whether a client with the same mod list can join.
FAQ
When does a mod belong in CLIENT_MODS, and when in SERVERMODS?
If the client needs the mod’s content or scripts, it must be loaded via CLIENT_MODS or -mod. Purely server-side extensions use SERVERMODS or -serverMod. The documentation of the respective mod is what matters.
Where do .bikey files go?
Copy them from the mod’s Keys subfolder into the server’s central keys/ folder. If the matching key is missing or belongs to a different mod version, the signature check fails when joining.
Do I have to update all mods immediately after every DayZ update?
First check the releases from the mod authors and back up the server. Update the server, mod files, and keys as one matching version set. Mixing old and new files often causes startup or connection errors.
When is a persistence wipe necessary?
Not after every update. A wipe only makes sense if map, economy, or mod changes are incompatible with the existing save state. Back up the storage_* folders and announce the data loss in advance.
Conclusion
With the right combination of @ModName folders, correctly stored keys, cleanly separated CLIENT_MODS/SERVERMODS entries, and a well-planned wipe and update rhythm, you can bring your DayZ server safely to the desired mod version — without frustrating clients with connection problems.