High-Density Photo Storage Solutions: A Cost-Effective Approach with RAID

With the advancement of photography, high-resolution images have become increasingly important. However, storing and accessing these images can be a challenge without the right storage solution. In this article, we explore the effectiveness of using a RAID 5 configuration for high-resolution photo storage and compare it with alternative solutions.

What I Use

I utilize a four-2TB ATA Hitachi HDD setup, configured as a RAID 5 volume with MDadm and LVM (Linux Volume Manager) for optimal performance and redundancy. This storage solution comprises two partitions on each drive: the smaller, striped, and mirrored partitions for system use, and the larger, RAID 5-configured partitions for storing high-resolution images.

Performance

The 5.4TB RAID 5 volume is extensively used for my high-resolution images. Reading tests indicate that the array can achieve read speeds as high as 420MB/s, with an average throughput of 252.7MB/s. The average random access time is 12.98ms over 1000 samples. The performance was tested under typical usage conditions, excluding the efficiency of predictive data caching algorithms. The chosen sample size of 30MB reflects the approximately 28–32MB file size of my 24Mpx camera captures in RAW format.

Alternatives

While solid-state drives (SSDs) can offer faster read and write speeds, the RAID 5 configuration remains an attractive option for several reasons. An M.2 SSD can significantly outperform traditional HDDs, but its high cost and limited capacity make it less suitable for large-scale photo storage. For instance, a new 2TB HDD can cost between $55 to $100, making a 6TB RAID 5 configuration around $220 to $400. Conversely, a single 2TB SSD would start at around $470, and a 6TB RAID 5 SSD could cost up to $1420. An M.2 2TB drive can range between $500 to $1228, making the RAID 5 configuration a cost-effective and expandable solution.

RAID is Main Storage, Not Backup

RAID 5, while offering data redundancy in the form of the ability to lose a single drive without losing data, is not a backup solution. Natural disasters such as fires, earthquakes, floods, etc., can wipe out the entire storage array. It is essential to have a proper backup solution, which should be stored away from the primary storage such as in the other side of the building, preferably off-site.

Backup Solutions

For backup, a single removable/external DAS (Direct Attached Storage) or Network Attached Storage (NAS) can be cost-effective. A basic 6TB external DAS can range from $200 to $400, while a NAS with similar capacity starts at $390. Cloud storage solutions are available for various price points, ranging from monthly to annual subscriptions. I opted for a USB3 single external HDD solution for my needs.

Conclusion

At an average data rate of 252.7MB/s, a 30MB RAW file can be accessed in just over 0.1 seconds, nearly lag-free. Using a RAID 5 of four HDDs, we achieve high storage capacities while maintaining high data read rates for editing. Many modern motherboards can connect up to six internal HDDs without additional interface cards, potentially increasing speeds and capacities. As more drives are added to the RAID 5, the maximum transfer rate can exceed the data bus speed.

Disclaimer: All prices and capacities are current as of 16th April 2018.