5. Maintenance5. Maintenance 5.1. Compaction 5.1.1. Database Compaction5.1.2. Views Compaction 5.1.2.1. Views cleanup 5.1.3. Automatic Compaction 5.1.3.1. Channels5.1.3.2. Channel Configuration5.1.3.3. Scheduling Windows5.1.3.4. Migration Guide 5.2. Performance 5.2.1. Disk I/O 5.2.1.1. File Size5.2.1.2. Disk and File System Performance 5.2.2. System Resource Limits 5.2.2.1. CouchDB Configuration Options 5.2.2.1.1. max_dbs_open 5.2.2.2. Erlang5.2.2.3. Maximum open file descriptors (ulimit) 5.2.3. Network 5.2.3.1. Connection limit 5.2.4. CouchDB 5.2.4.1. DELETE operation5.2.4.2. Document’s ID 5.2.5. Views 5.2.5.1. Views Generation5.2.5.2. Built-In Reduce Functions 5.3. Backing up CouchDB 5.3.1. Database Backups5.3.2. Configuration Backups5.3.3. Log Backups