Guide to Migrating Slack Data to Mattermost

Migrating from Slack to Mattermost offers cost savings, data control, and customization advantages. Mattermost’s self-hosted model ensures full ownership of your data, making it ideal for industries with strict compliance needs. Plus, its flat-fee pricing can save money for growing teams. Here's what you need to know:

• Why Switch?
  • Data Ownership: Self-hosted for full control.
  • Cost-effective: Flat-fee pricing, no per-user charges.
  • Compliance: Supports GDPR and secure data portability.
  • Customization: Open-source platform for tailored solutions.
• Migration Steps:
  1. Export Slack data (public channels on free plans, private channels/DMs on paid plans).
  2. Convert Slack exports to Mattermost format using mmetl.
  3. Import data into Mattermost and verify.
  4. Activate user accounts and resolve any issues.
• Tools You’ll Need:
  • mmetl for data conversion.
  • mmctl for managing imports and configurations.

Switching to Mattermost ensures better control, lower costs, and a tailored communication platform for your team. Follow the migration steps carefully to avoid data loss and ensure a smooth transition.

How To Export Workspace Data On Slack

Getting Ready for the Migration

Switching to Mattermost can bring plenty of benefits, but preparation is key to making the migration process smooth. This involves setting up your Mattermost server, gathering the right tools, and understanding the steps involved.

Steps in the Migration Process

Migrating to Mattermost involves several clear phases, each with specific tasks and considerations:

Required Tools and Setup

The main tool for converting Slack data into Mattermost format is the mmetl utility, which ensures the data is properly transformed. After importing, you can use the mmctl command-line tool to manage channels and other configurations.

Here’s what your Mattermost server setup needs:

• Storage Configuration: Make sure there's enough storage for imported data, system logs, and file attachments. Set appropriate size limits for uploads ^[2].
• Server Organization: Create a dedicated team in Mattermost to keep the imported data well-organized ^[1].

Mattermost's bulk import tool is especially helpful for larger migrations, as it allows you to pause and resume without duplicating data ^[2]. To avoid technical hiccups, temporarily disable antivirus software during the upload process.

With your tools and server ready, the next step is exporting your Slack data for conversion.

Exporting Slack Data

To move your Slack workspace data to Mattermost, you'll first need to export it properly. This step is crucial to avoid losing information and make the transition smooth.

How to Export Data from Slack

Start by ensuring you have administrative access to your Slack workspace. The export process varies depending on your subscription plan, with free plans being more limited compared to paid ones.

1. Access Workspace Settings

Go to your Slack workspace settings via the admin dashboard.

2. Export and Download

Select the export type based on your plan. Free plans allow exports of public channels only, while Business+ and Enterprise plans also include private channels and direct messages (DMs). Once ready, Slack provides a ZIP file containing your workspace data in JSON format.

Here's a breakdown of what’s included in the export:

Handling Files and Extra Data

Slack’s standard export doesn’t include files or email addresses. Download file attachments manually through Slack and organize them for migration. You can export the user list from Slack’s admin panel to map usernames to email addresses. Be sure to validate email addresses before importing them into Mattermost.

For larger datasets, consider using Mattermost CLI tools like mmctl to handle the data effectively ^[1]. This is especially helpful when maintaining user associations is a priority ^[2].

Before moving forward, double-check that all exported data is complete and correctly formatted. This step can help you avoid issues like data loss or corruption.

Once your Slack data is exported and organized, you’re ready to convert it for use in Mattermost.

Converting Slack Data for Mattermost

After exporting your Slack data, the next step is to convert it into a format that works with Mattermost. To do this, you'll use Mattermost's official tool, mmetl, which transforms Slack's exported data into a format compatible with Mattermost's bulk import system.

How to Use the mmetl Conversion Tool

Start by downloading the mmetl tool from Mattermost's official repository. Make sure your Slack export ZIP file is in your working directory. Then, run this command to convert your Slack export into a Mattermost-compatible JSONL file:

mmetl convert slack_export.zip mattermost_import.jsonl

This tool processes everything - messages, users, channels, and timestamps - while keeping their structure and order intact. This way, your communication history is transferred accurately.

Validating the Converted Data

Before importing, it's a good idea to validate the converted file. Use this command:

mmetl validate mattermost_import.jsonl

Take a moment to review the JSONL file. Check for:

• Message content and formatting
• Correct user associations
• Proper channel structures

If you spot validation errors, revisit the export or conversion steps to fix any issues, such as user mapping errors, incorrect channel permissions, or timestamp formatting problems ^[1][2].

Once your data is fully converted and passes validation, you can proceed to import it into your Mattermost server.

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Importing Data into Mattermost

Once your data is validated and ready, the next step is to bring it into your Mattermost server.

Preparing the Mattermost Server

Before you start, make sure your Mattermost server is set up properly. This includes having enough storage, enabling file attachments, and ensuring you have admin permissions. It's a good idea to create a new team to organize the imported content, especially if you're handling multiple Slack workspaces. For better organization, import each Slack workspace into its own team first. Later, you can restructure channels using the mmctl tool ^[1].

Uploading and Importing Files

First, compress your validated JSONL file into a ZIP file. Then, use the mmctl tool to upload and process it with these commands:

• Upload the file: mmctl import upload <file>.zip
• Start the import: mmctl import process --bypass-upload <file>.zip --local

Keep an eye on logs for any errors and ensure you have enough storage space throughout the process.

"Execute the bulk import command as the mattermost user to avoid file permission issues. Temporarily disable antivirus or other services that might block attachment uploads. Ensure there is enough free space for logs on the Mattermost server and database server" ^[2].

For larger migrations, take these extra precautions:

• Test the process in a staging environment first.
• Monitor your database performance closely.
• Temporarily disable antivirus software.
• Confirm there's enough disk space for logs and imports ^[1][2].

The import tool can be used on live systems, but keep in mind that any changes made to imported channels or messages during the process might be overwritten ^[2]. Common problems, like file permission errors or storage issues, can usually be fixed by adjusting your server settings or freeing up space ^[2][3].

Final Steps After Migration

Once you've successfully imported your data into Mattermost, a few final steps will help your team get started smoothly.

Activating User Accounts

To ensure users can log in and begin collaborating:

• Use Mattermost's Password Reset feature to send activation emails, allowing users to set their credentials securely ^[1].
• Set up SSO (Single Sign-On) if your organization uses it.
• Double-check admin and moderator permissions, especially system admin privileges, to avoid access issues.

Addressing Common Problems

Be prepared to tackle these typical migration issues:

Channel Access

• Use mmctl to verify channel memberships and permissions.
• Confirm that private channel settings are intact.
• Ensure users can access the channels assigned to them.

File Attachments

• Check storage permissions if files are missing.
• Test file preview functionality to ensure it's working correctly.

For additional help, you can:

• Visit the Mattermost forums for technical support.
• Refer to the official documentation.
• Join community support channels for advice ^[2].

Setting up a feedback channel is also a smart move. It allows users to report issues, and you can address them quickly. This keeps communication clear and ensures a smoother transition.

"Actively engage with users through a dedicated support channel and promptly address any concerns or issues raised" ^[1].

Keep an eye on system performance after the migration and consult Mattermost's documentation for advanced optimization tips if needed. These steps will ensure your team is ready to collaborate effectively in the new environment.

Other Tools for Team Collaboration

When transitioning from Slack to Mattermost, it's helpful to explore the broader range of collaboration tools available. This can ensure that your organization selects the platform that best fits its needs. While Mattermost is a strong choice for many teams, understanding the options adds confidence to the migration decision.

Slack Alternatives

Slack Alternatives offers a detailed directory for comparing team collaboration platforms, focusing on the features that modern teams rely on most:

When evaluating collaboration tools, here are some factors to weigh:

• Self-hosting options: Critical for organizations that need full control over their data.
• Security measures: Look for features like end-to-end encryption and compliance with industry standards.
• Integration capabilities: Ensure compatibility with your current workflows and tools.
• Cost considerations: Assess long-term pricing and overall value.

Choosing the right collaboration platform requires balancing your immediate needs with future objectives. Resources like Slack Alternatives provide helpful feature comparisons and practical advice to guide your decision.

For teams that prioritize self-hosting and data control, Mattermost emerges as a strong option, making the migration a smart move.

Conclusion: Tips for a Smooth Migration

Switching from Slack to Mattermost requires careful planning and execution. Here's how to make the process as smooth as possible.

Pre-Migration Preparation

Start by ensuring your Mattermost server meets all the necessary technical specs and can handle Slack's data format ^[1]. Laying this groundwork helps avoid hiccups and keeps the process running smoothly.

Tools and Validation

To handle the migration, rely on mmetl for converting and validating Slack data, and mmctl for importing it into Mattermost ^[2]. These tools are essential for maintaining data accuracy during the transfer.

Post-Migration Steps

After the migration, focus on these tasks:

• Activate user accounts using Mattermost's Password Reset feature ^[1].
• Double-check that imported data matches the original Slack content ^[2].
• Ensure all attachments are correctly linked and accessible ^[1].

Completing these steps ensures your team can start collaborating in Mattermost without any disruptions.

Technical Details

Run all commands as the mattermost user to avoid permission issues ^[2]. Taking care of these details upfront helps sidestep common technical challenges during the migration.

FAQs

Can I export data from Slack?

Yes, you can export data from Slack using the admin dashboard. On the free plan, exports include only public channels. To export private channels and direct messages, you'll need a paid plan and approval from Slack support. Keep in mind that file attachments aren’t part of standard exports - you’ll need to download and organize them separately for migration.

How can I verify the migration was successful?

After migration, use mmctl to confirm everything imported correctly ^[2]. Check for these key points:

• Complete message history
• Accurate user associations
• Correct channel organization
• Access to file attachments

What if I have a large dataset?

For large datasets, Mattermost CLI tools are your best bet. They help manage errors, handle large volumes, and let you pause and resume without duplicating data ^[1][2]. Test the process in a staging environment first, and keep an eye on database performance during the migration.

What should I do about missing emails?

If email addresses are missing in the exported data, create temporary placeholder emails and update them manually before completing the import ^[1][2]. This ensures smooth communication after the migration. Properly managing user details is key to avoiding disruptions.