High-complexity migration: preparing Invision Community 5 at large scale

Upgrading a large Invision Community from v4 to v5 is not linear work. In this DirectAdmin scenario, the documented path required practical contingencies to deliver a safe and testable rollout.

1) Storage challenge: 350 GB without duplication

Observed footprint:

• application core: < 1 GB
• media (uploads/photos): ~310 GB
• database: tens of GB

To avoid expensive media duplication:

1. used rsync for essential code/config structure.
2. used symlinks from staging to existing media storage.

Outcome: full staging usability with minimal extra storage.

2) Isolation via hosts and -TESTINSTALL limitation

While -TESTINSTALL is the recommended licensing pattern, it was not sufficient in this specific environment.

Applied workaround:

1. replicate stack to a separate server.
2. force local hostname resolution through hosts file.

This enabled realistic validation without public DNS cutover conflicts.

3) Database integrity through CLI

For large datasets, web import is fragile. Import was done via shell:

pv backup_producao.sql | mysql -u user_staging -p banco_staging

pv provided real-time throughput and progress visibility.

4) Hands-on upgrade when CLI path fails

Recommended CLI upgrader did not behave reliably in this environment.

Contingency strategy:

1. execute upgrade from browser with strict supervision.
2. monitor MySQL processlist continuously.
3. run heavy/blocked SQL operations manually when needed.

This kept large-table transitions under control.

5) Permissions, HTTP 500, and runtime tuning

Classic DirectAdmin staging issue: 500 Access Denied.

In IC5, critical files and directories must match PHP-FPM runtime user/group (for example site1:site1). Incorrect ownership caused startup failures.

Additional tuning:

1. centralized runtime directives to avoid .user.ini / .php.ini conflicts.
2. fixed invalid session.save_path.
3. increased memory_limit and max_post_size for heavy migration phases.

Operational success checklist

• [x] Isolated staging on separate server with hosts routing.
• [x] Selective sync using rsync + media symlinks.
• [x] CLI database import with pv visibility.
• [x] Active SQL/process monitoring during upgrade.
• [x] Ownership/permission hardening for PHP-FPM runtime user.

Large IC v4 to v5 upgrades require adaptability when official automation paths break. Controlled execution, observability, and strict staging isolation turn a risky migration into a predictable technical delivery.

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