iOS Storage Best Practice

Tech Talks

Storage Inventory

Storage Inventory Questions

• What is this file ?
• Why is it being stored ?
• Is it in the correct place ?
• Should this be backed up ?

iCloud Drive

• Accessible across all devices
• Cached locally
• Automatically uploaded to iCloud
• Requires file coordination

Documents Directory

• User-visible content
• Accessible in Files app
  - Support “Open in Place”
  - Support “File Sharing Enabled”

• Storage Settings management

Storage Locations

• iCloud Drive
• Documents
• Application Support
• Caches
• Temporary

Application Support Directory 📁

• Required files
• Can be hierarchical
• Persistent
• Included in iCloud and iTunes Backups
• Reported in “Documents & Data”

Caches Directory 📁

• Purgeable or transient content
• Good for downloadable storage
• Not included in backups
• Reclaimed by OS if needed

Temporary Directory 📁

• Transient files
• Remove when done
• Not included in backups

Best Practices

• Exclude files from backups
  - NSURLIsExcludedFromBackupKey
• Handle restored data gracefully
  - 64 bit vs 32 bit content
  - Version your content
• Cloud or Local ?
  - Choose only one
• NSURL volume capacity details
  - NSURLVolumeAvailableCapacityForImportantUsageKey
  - NSURLVolumeAvailableCapacityForOpportunisticUsageKey