TL;DR
TrueNAS 27 is the next major release of TrueNAS, built on OpenZFS 2.4 and Linux kernel 6.18. It was previously numbered TrueNAS 26. RC.1 is the first release candidate, and TrueNAS 27.0 is scheduled for early December 2026. Highlights:
- TrueSearch and WebShare: server-side search across file names, metadata, and content, with macOS Spotlight integration and browser access to your files from any device.
- Fusion Pools 2.0: RAIDZ special vdevs, ZIL on the special vdev, and Live Dataset Tiering on TrueNAS Enterprise to seamlessly move datasets between flash and disk to provide the required performance profile.
- Stateful SMB failover: SMB sessions survive a controller failover on TrueNAS Enterprise HA systems.
- OpenZFS 2.4 and Linux kernel 6.18: faster dedup writes, less fragmentation, default quotas, and fully supported LXC containers.
- TrueNAS Object Interface (Early Access): native S3 access to ZFS datasets on every TrueNAS edition.
1. Introduction
TrueNAS 27 RC.1 is here. If you’ve been following along, this is the release we’ve been testing as TrueNAS 26.BETA.3. You can read why we renamed it in our TrueNAS 27 announcement. The schedule is unchanged, and TrueNAS 27.0 still releases in early December 2026. RC.1 also adds some new capabilities, including the TrueNAS Object Interface.
Storage releases are usually measured in capacity and throughput. TrueNAS 27 has plenty of those numbers, but the more interesting story is how much less effort it takes to manage. Here’s what that looks like in RC.1.
2. What’s in TrueNAS 27
TrueNAS 27 brings together the features we have been building and testing through the TrueNAS 26 beta cycle. At a glance:
- Access your files from any browser: WebShare provides a fully functional, SMB/NFS-compatible web interface to all your files. It even integrates with Active Directory (AD).
- Find anything, from any device: TrueSearch indexes the files stored in TrueNAS, with Spotlight Search integration for macOS and WebShare as the browser portal.
- Flash where you need it: Fusion Pools 2.0 introduces RAIDZ special vdevs, additional log device options, and Live Dataset Tiering on TrueNAS Enterprise to move datasets between flash and spinning disk without disrupting clients.
- Stateful SMB failover: SMB sessions carry over a controller failover on TrueNAS HA systems.
- Performance upgrades with the update: OpenZFS 2.4, Linux kernel 6.18, and WebUI improvements.
- Object interface to your ZFS data: S3 access to existing or new datasets, alongside SMB, NFS, AD, and WebShare.
Each of these gets its own section below, and a deeper look in the coming weeks.
3. Find Anything, Access from Any Device
We first showed TrueSearch and WebShare back in January. With TrueNAS 27 RC.1, they’re ready for you to try:
- TrueSearch: Finding a file on a large NAS usually means walking the directory tree, or asking whoever saved it. TrueSearch is a server-side index of file names, metadata, and content, so results come back in seconds instead of minutes. Mac users don’t have to change how they work, either. With Spotlight Search enabled on an SMB share hosted on TrueNAS, Finder searches it the way it natively searches your local macOS device. TrueNAS does the indexing ahead of time, so nobody’s Mac is crawling the share over the network. For media teams, that turns a shared volume into a lightweight asset library.
- WebShare: WebShare brings the same data to a browser, tablet, or phone, with your ACLs and permissions intact. Preview media, browse snapshots, and share or collect files, much like Dropbox, without handing your company’s data to a public cloud. Nobody has to reorganize a share or retrain users; the index does the work. WebShare and TrueSearch require TrueNAS Connect. More in our upcoming TrueSearch deep dive.
4. Fusion Pools 2.0 and Live Dataset Tiering
With flash prices up more than 300% and a roughly 20X cost gap between flash and HDD raw capacity, TrueNAS has continued to refine and reinvigorate the hybrid storage design it was built around. TrueNAS 27 RC.1 is where you can use the new features, including live tiering of data between a performance-focused flash tier and a larger, capacity-oriented main pool.
Fusion Pools 2.0: A Fusion Pool is a ZFS pool that pairs flash special vdevs with disk-based data vdevs, so metadata, small files, and selected datasets run at flash speed while bulk data stays on disk. Special vdevs have been available for several years in TrueNAS, but have been limited to mirror topologies only for redundancy. TrueNAS 27 RC.1 introduces support for RAIDZ special vdevs, allowing for greater flexibility and letting you make the most of available SSD capacity.
Special vdev as SLOG: Alongside the new layout options for the special vdev, the special vdev can now act as part of the ZFS log device chain for handling synchronous writes. If a dedicated log device is present, it takes priority. But in case of a device failure, or where a mixed workload makes sense initially, the special vdev absorbs these writes to notify the client workload that the write is on stable storage and protected against sudden power loss.
Live Dataset Tiering: The upgraded flexibility and performance of these special vdevs can now be used through the new “Live Dataset Tiering” feature in TrueNAS Enterprise 27 RC.1, which allows for transparent migration of data blocks between the performance and capacity tiers of your pool without disrupting clients.
5. Stateful SMB Failover on High-Availability Systems
On a TrueNAS HA system, two controllers are installed in one chassis, and share access to all of the storage devices. In case of hardware faults, the secondary controller takes over management of the traffic, and brings the storage pool back online. For SMB users, this failover used to mean a dropped session. Connected clients had to reconnect and sometimes re-authenticate, and large copy jobs in progress could fail and have to start again, interrupting workflows and frustrating end-users.
TrueNAS 27 adds stateful SMB failover, keeping SMB session states consistent across a controller failover, so clients pick up their existing sessions without re-authenticating. Large transfers keep going from where they were before. This matters most where files are big and time is short: editors working on shared media, digital surveillance systems, and scanners or instruments writing multi-GB files straight to the NAS.
Stateful SMB failover is available on TrueNAS Enterprise HA systems, and you turn it on in the SMB service settings. The upcoming deep dive covers the details and requirements.
6. Performance and Platform Updates: OpenZFS 2.4, Linux 6.18, WebUI
TrueNAS 27 also includes upgrades you get just by updating:
- OpenZFS 2.4 provides a number of tangible improvements. Dedup writes are up to 25% faster, encryption is faster on CPUs with AVX2 extensions (all currently shipping TrueNAS Enterprise appliances are AVX2-capable), and smarter write allocation reduces fragmentation and keeps pools responsive as they fill up. Admins also get default user, group, and project quotas, and scrubs that can be limited to a set time window.
- Underneath, the Linux kernel moves to 6.18, with updated drivers for Broadcom tri-mode HBAs, Gen5 PCIe switching, and new NVIDIA GPUs. Linux containers (LXC), introduced as experimental in 25.04 and matured in 25.10, are now fully supported.
- In the WebUI, alerts now explain how to fix the issue they report, user management takes fewer clicks, and self-encrypting drives can be managed without the command line.
Most of this happens in the background and needs no tuning.
7. TrueNAS Object Interface: Native Access to ZFS Data
Object storage (S3-API) has become the default target for backups, archives, and a growing list of applications. Traditionally, object storage in TrueNAS has been provided via a containerized third-party application. As a late addition to TrueNAS 27, object storage is also available as a native TrueNAS service. This provides concurrent, universal access to stored data whether you are using SMB, NFS, WebShare, and now via the S3 protocol. The design is simple: each object storage bucket is a ZFS dataset. Your object data gets the same snapshots, quotas, replication, and data integrity as everything else on your TrueNAS system, and you manage it from the same WebUI.
RC.1 already covers the core S3 API that applications depend on, including multipart uploads, object tagging, bucket and object ACLs, versioning and immutability. That makes it a practical, immutable target for S3-compatible backup software.
The TrueNAS Object Interface runs on every TrueNAS edition, with no capacity limits, including in a completely offline mode for air-gapped environments. It speaks the standard S3 API, so common S3 clients and SDKs will be supported. If yours doesn’t work, tell us. Versioning and Object Lock features require a TrueNAS Connect Plus license or TrueNAS Enterprise systems.
TrueNAS 27 RC.1 introduces the TrueNAS Object Interface as an Early Access feature. Early Access means we want your feedback. Try it with your applications, tell us in the forums what works and what doesn’t, and help shape it on the way to full production status in 2027.
8. The Road to TrueNAS 27
RC.1 is the first release candidate for TrueNAS 27. From now until the 27.0 release in early December, the focus shifts to stability, polish, and your feedback. If you run early adopter or test systems, this is a good time to try it. Production systems should wait for 27.0.
TrueNAS 27 is also our first release on an annual cadence. One major release a year gives each version more time for design and testing, and it means fewer major upgrades for you to plan around.
9. Try It and Tell Us
TrueNAS 27 RC.1 will be available this week. This blog will be updated with links to the downloads and release notes once they are available.
Your feedback shapes what ships in TrueNAS 27. Share what works and what doesn’t on the TrueNAS Community Forums, and report bugs directly from the WebUI. We especially want to hear from anyone trying the TrueNAS Object Interface with their applications.
Over the coming weeks, we’ll take a deeper look at TrueSearch, Fusion Pools 2.0, stateful SMB failover, and the Object Interface, one post at a time. Follow along on the TrueNAS blog.
Thank you to everyone who tested and reported bugs during the beta cycle. TrueNAS 27 RC.1 is ready for your test systems.
Frequently Asked Questions
What’s new in TrueNAS 27?
TrueNAS 27 adds TrueSearch and WebShare, Fusion Pools 2.0 with RAIDZ special vdevs and Live Dataset Tiering, stateful SMB failover on Enterprise HA systems, OpenZFS 2.4 on Linux kernel 6.18, and the TrueNAS Object Interface for native S3 access (Early Access).
Is TrueNAS 27 the same release as TrueNAS 26?
Yes. TrueNAS 27 is the release previously tested as TrueNAS 26 BETA. It was renamed with the release of RC.1 because most users will deploy it during 2027.
When will TrueNAS 27.0 be released?
TrueNAS 27.0 is scheduled for early December 2026. RC.1 is intended for early adopters and test systems. Production systems should wait for 27.0 or even General Availability.
What is a Fusion Pool in TrueNAS?
A Fusion Pool is a ZFS pool that pairs flash special vdevs with disk-based data vdevs, so metadata, small files, and selected datasets run at flash speed while bulk data stays on disk. TrueNAS 27 adds RAIDZ special vdevs and, on TrueNAS Enterprise, Live Dataset Tiering.
What is the TrueNAS Object Interface?
The TrueNAS Object Interface is a native, S3-compatible object storage service built into TrueNAS 27. Each bucket is a ZFS dataset, so the same data can be accessed concurrently over S3, SMB, and NFS, with the same snapshots, quotas, and replication as your existing datasets. It’s an Early Access feature in RC.1 and runs on every TrueNAS edition with no capacity limits, including offline and air-gapped environments. Versioning and Object Lock require TrueNAS Connect Plus or TrueNAS Enterprise.
Which TrueNAS 27 features require TrueNAS Connect or TrueNAS Enterprise?
WebShare requires TrueNAS Connect. Spotlight Search requires TrueNAS Connect or an Enterprise license. Object Interface versioning and Object Lock require TrueNAS Connect Plus or TrueNAS Enterprise. Live Dataset Tiering is a TrueNAS Enterprise feature, and stateful SMB failover requires a TrueNAS Enterprise HA system.
Can I search TrueNAS from a Mac?
Yes. With Spotlight Search turned on in the SMB service, macOS Finder can search TrueNAS SMB shares by file name, content, and type, using an index TrueNAS builds ahead of time. Set the Finder search scope to the share, because searching “This Mac” doesn’t include network shares. Encrypted datasets aren’t indexed.