The Road to RAID-Z Expansion

Expanding storage capacity has long been a challenge for RAID-Z users. Traditionally, increasing the size of a RAID-Z pool required adding an entirely new RAID-Z vdev, often doubling the number of disks—an impractical solution for smaller storage pools with limited expansion options.

To address this, the FreeBSD Foundation funded the development of RAID-Z expansion, making it both practical and easy to implement. Led by Matt Ahrens, a ZFS co-creator, the feature underwent years of rigorous testing and refinement. Although the pandemic caused some delays, the project was feature complete in 2022. Additional integration steps followed, and the feature is now generally available in the OpenZFS.

Thank You for Your Support

After years of development, industry collaboration, infrastructure testing, and nearly $100,000 investment, we are so excited to see RAID-Z expansion in the recent release of OpenZFS 2.3. We’re also grateful to iXsystems for their efforts in finalizing and integrating this feature into OpenZFS.

This marks a significant milestone in the evolution of the ZFS filesystem and reinforces its position as a cutting-edge open source filesystem for modern storage use cases.

This development work happened because of your donations to the FreeBSD Foundation. We couldn’t have made this financial commitment without your help. Thank you to all our supporters, large and small.