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With Samba version 4.22, support for “reflink copies” has been extended. Reflink stands for Reference Links: a feature that significantly speeds up the copying of large files by creating only references to data blocks on supporting file systems.

The feature was developed by the Samba team at SerNet GmbH in close cooperation with storage manufacturer FAST LTA, who commissioned the implementation. The aim was to fulfill an essential step so that storage systems such as FAST LTA's Silent Bricks can also support Veeam's Fast Clone feature for SMB access under Linux.

Technical background

“Reflink copies” use features of modern file systems such as Btrfs, XFS, ZFS, or ReFS to make data duplication more efficient. With SMB-based access, clients can use SMB protocol features for “reflink copies,” provided that the server and its file system support this. Previously, support in Samba was limited to the Btrfs file system.

In Samba 4.22, general support is now enabled for all file systems that support the “reflink copies” functionality – by using the generic Linux ioctl FICLONERANGE. This enables the use of backup software such as Veeam, which regularly creates complete or differential copies of large amounts of data, with file systems other than Btrfs, ZFS, and XFS. Thanks to the extension in Samba, Linux-based SMB backends – such as those provided by FAST LTA with the Silent Bricks storage system – can now also support Veeam's Fast Clone. This significantly improves performance for so-called “forever incremental” and “synthetic full” backups. The result is a reduction in storage requirements, I/O load, and backup times.

Upstream tops proprietary

The technical implementation was carried out by the Samba team at SerNet lead by Ralph Böhme, who has been working on central components of the project for many years as a member of the Samba Core Team. The code has been fully integrated upstream and is now part of the official Samba release series 4.22.

“For us, it is an important signal when manufacturers such as FAST LTA specifically focus on the further development of open source components,” says Ralph Böhme. “Such contributions not only strengthen the functionality of individual systems, but also the sustainability and openness of the overall architecture.”

Christian Rogg, lead developer at FAST LTA, is enthusiastic about the collaboration with SerNet: “It started out as just an idea. The implementation with SerNet was extremely professional, and the results are impressive. Veeam users now save up to 50% in storage capacity and backup time with Fast Clone Support with Silent Bricks.”

Joint development initiatives

As part of its development services, SerNet offers specific enhancements and customizations of Samba – especially for manufacturers, OEMs, and operators of complex infrastructures. The aim of such collaborations is to combine individual requirements with open source practice: Developments are designed transparently, implemented with technical expertise, and merged into the official Samba source code base for the benefit of Samba users worldwide

Contact us for more development opportunities with SerNet!

What is probably the world's first productive setup of Samba and Linux clients with SMB3 UNIX Extensions is now up and running at Frankfurt University of Applied Sciences (UAS). Björn Jacke from the SerNet Samba team recently worked with colleagues from the university's IT department to equip the Samba server and connected Linux clients with this new feature for academic purposes.  

Frankfurt UAS had consciously decided not to use dual protocols SMB and NFS. Instead, it now relies on uniform integration with SMB3: Samba's rights and sharing management offers much greater flexibility and easier administration. Without the Unix Extensions, students using Linux workstations were previously restricted in that symlinks or Unix commands such as chmod did not behave as they would on a typical POSIX/Linux system. The operations could not be mapped directly via the SMB protocol. Jacke: “With the new SMB3 UNIX Extensions, Linux clients now work perfectly with SMB mounts from Samba servers, enabling optimal integration without compromise. This makes studying at Frankfurt University even more enjoyable for students.”

Samba 4.22 with SMB3 Unix Extensions

The SMB3 UNIX Extensions feature is available since Samba version 4.22, which was released in April 2025. The topic also dominated this year's sambaXP and can be reviewed in several recordings published on the SAMBA+ YouTube channel.

SerNet has already incorporated some additional features into the current SAMBA+ packages, which will only be part of Samba from version 4.23 onwards in fall 2025.

SerNet: Worldwide partner for Samba projects

Support – remote or directly onsite – is part of the core business of SerNet's Samba team. The team supports companies and organizations in setting up, maintaining, and optimizing Samba infrastructures. The project implementation in Frankfurt shows how practical know-how and technological development come together at the customer's site.

How can we assist you with your Samba environment?

SerNet offers professional assistance with all questions relating to Samba, SMB, and Active Directory – from planning and implementation to ongoing support and development projects. Find out more about our services or contact us directly.

Following the official release of Red Hat Enterprise Linux (RHEL) 10 on May 20, 2025, the Samba team at SerNet swiftly released SAMBA+ 4.22 for RHEL 10. Subscribers can seamlessly access these latest packages.

Additionally, SAMBA+ 4.22 packages are immediately available for the following binary-compatible distributions:

• AlmaLinux 10
• CentOS Stream 10
• Oracle Linux 10
• Rocky Linux 10

SAMBA+ is particularly suitable for RHEL environments due to its optimized integration, robust performance, and consistent security updates. Built specifically with enterprise needs in mind, SAMBA+ ensures reliable interoperability between Linux/Unix servers and Windows-based clients. Moreover, regular, timely updates and comprehensive testing guarantee compatibility with RHEL's latest security enhancements and system improvements.

SAMBA+ 4.22 includes key enhancements such as SMB3 Directory Leases and SMB3 POSIX Extensions, further boosting performance, efficiency, and compatibility in enterprise scenarios.

For further details and to download your SAMBA+ packages, have a look at our version overview. More information and pricing can be found in the USD shop or the EUR shop. Existing subscriptions include access to the new packages.

The next installment in the webinar series "Setting up SAMBA+ on AIX with SAMBA+" will take place on May 27 (10 to 11 pm CEST). This session is designed to enhance technical skills and knowledge. 

Secure your spot and find more information here.

Webinar Highlights:

• Expert Guidance: Björn Jacke, a renowned expert, will provide step-by-step instructions on setting up Samba with SAMBA+ on AIX, IBM's Unix operating system.
• Active Directory Integration: Learn how to integrate Samba into an Active Directory environment seamlessly.
• Troubleshooting Tips: Gain insights and tips to overcome common challenges.
• Parameter Settings: Explore specific parameter settings in AIX for optimal performance.
• Interactive Q&A: An opportunity to ask questions and receive answers in real-time from the expert.

This webinar will be held in English. Additional dates will be announced shortly.