Scaling Self-Hosted Nextcloud to 5,000 Users

핵심 내용

1. Move from SQLite to PostgreSQL before scaling. SQLite serializes writes and becomes the bottleneck long before user count does.
2. Separate Redis roles. Use one instance for locking, one for caching, and one for session storage, or at least separate databases with distinct eviction policies.
3. Tune PHP-FPM for steady state. Set pm to static with a worker count derived from available memory, not dynamic, which thrashes under bursty load.
4. Enable file locking with Redis. The default database locking creates row contention on every upload and sync.
5. Offload background jobs. Run occ background:ajax or a cron worker on a dedicated node so heavy maintenance does not block user requests.
6. Index the database deliberately. Add indexes for oc_filecache and oc_share introduced by your actual query patterns, not the default set.
7. Cache aggressively at the edge. Put a reverse proxy with long-lived cache headers in front of static assets and thumbnails.
8. Measure before tuning. Use the built-in server info endpoint and database slow query logs to find the actual bottleneck.

Architecture

The request path runs from the edge proxy through PHP-FPM into PostgreSQL for metadata and Redis for locking and cache. Background jobs and previews run out of band. Scaling means keeping the database off the hot path for reads, which is why Redis carries cache and lock state while PostgreSQL holds the durable record.

Production configuration

; /etc/php/8.3/fpm/pool.d/nextcloud.conf
pm = static
pm.max_children = 64
pm.start_servers = 64
pm.min_spare_servers = 64
pm.max_spare_servers = 64
pm.max_requests = 500
php_admin_value[memory_limit] = 512M
php_admin_value[opcache.enable] = 1
php_admin_value[opcache.memory_consumption] = 256

'memcache.local' => '\OC\Memcache\Redis',
'memcache.locking' => '\OC\Memcache\Redis',
'memcache.distributed' => '\OC\Memcache\Redis',
'redis' => [
  'host' => '127.0.0.1',
  'port' => 6379,
  'timeout' => 0.0,
  'password' => '',
  'dbindex' => 0,
],
'dbtype' => 'pgsql',
'dbhost' => '127.0.0.1',
'dbname' => 'nextcloud',
'dbuser' => 'nextcloud',
'dbpassword' => 'change-me'

*/5 * * * * www-data php /var/www/nextcloud/cron.php
# or, for ajax mode safety:
sudo -u www-data php /var/www/nextcloud/occ background:cron

Edge cases from production

• Large file uploads fail when client_max_body_size and PHP upload limits disagree; set both to the same value and test with a real large file.
• Redis eviction under memory pressure drops locks and corrupts uploads; set maxmemory-policy to noeviction for the locking instance.
• Federation shares across instances require matching protocol versions; mismatched versions silently fail.
• Previews for video and office documents consume CPU; disable preview generation for file types you do not need.

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