In video post-production environments, especially those handling both large single-file video clips and high-resolution image sequences, storage performance is crucial. Choosing the right RAID configuration and tuning its parameters—particularly stripe size—can make a significant difference in workflow efficiency.

This article explores how stripe size impacts RAID 5 and RAID 6 performance in small arrays (4–12 drives), providing practical advice to optimize storage for mixed workloads common in video editing and post-production.

The Importance of RAID in Video Editing

RAID (Redundant Array of Independent Disks) offers both performance improvements and data redundancy. For editors working with 4K, 6K, or even 8K footage, optimal performance can reduce rendering times, accelerate timeline responsiveness, and prevent bottlenecks when working on high-resolution image sequences.

RAID 5 and RAID 6 are popular choices for media workflows due to their balance of performance and redundancy:

• RAID 5: Uses block-level striping with one disk worth of parity, suitable for read-intensive workloads.
• RAID 6: Similar to RAID 5 but with double parity, offering higher fault tolerance—useful in environments where data safety is paramount.

How Stripe Size Influences Performance

Stripe size—also called stripe block size—is the amount of data written to each disk before moving to the next in the array.

• Small stripe size (e.g., 64KB): Optimized for small, random I/O, and many small files.
• Large stripe size (e.g., 1MB): Better suited for large, sequential reads/writes like large video files.

Impact on RAID Arrays

In RAID arrays, the choice of stripe size impacts how efficiently the array can read/write data for various workloads:

• Large files (video clips): Sequential access benefits from larger stripe sizes, allowing entire files to be read or written in a continuous stream, minimizing disk seek overhead.
• High-resolution images or image sequences: Small or moderate stripe sizes improve random access, beneficial when editing isolated frames or small chunks randomly accessed during editing.

Optimizing for Mixed Video and Image Workloads

Approach to Stripe Sizing:

1. For predominantly large video files and sequences:

   • Use a larger stripe size (256KB to 512KB, or even 1MB).
   • Benefits: Faster sequential read/write speeds, reduced seek overhead, and smoother timeline playback.

2. For workflows involving both large files and high-resolution image sequences:

   • Consider a mixed approach:
     • Split your RAID array into sub-volumes with different stripe sizes tailored to each workload.
     • Or select a moderate stripe size (128KB or 256KB), balancing sequential and random access performance.

3. RAID type considerations:

   • RAID 5 with larger stripe sizes performs well with large sequential data but may experience bottlenecks with random I/O.
   • RAID 6 offers extra security; choosing an appropriate stripe size becomes even more critical here because the parity calculations add overhead, especially with high stripe sizes.

Additional considerations:

Write vs. Read Performance

• Larger stripe sizes improve read speeds for sequential large files, ideal for playback and rendering.
• Write speeds can also benefit, but extremely large stripe sizes may reduce efficiency during small file or high-random I/O tasks.

Parity Overhead

With RAID 5 and RAID 6, parity calculations introduce overhead, especially during write operations. Larger stripe sizes reduce the number of parity calculations per operation, improving write performance during sequential large-file transfers.

Practical Recommendations for Video Editors

Example Configuration:

• For 8 drives, a stripe size of 256KB strikes a good balance for mixed workloads, offering good sequential speeds and acceptable random access performance.

Final Thoughts: Preparing Your RAID for Mixed Use

• Test your workload: Run benchmarks simulating your typical editing sessions.