This content was auto-generated from Fusion SMB documentation and is pending SME review. Please verify accuracy before using in partner-facing contexts.
Frequently Asked Questions
This page collects common technical questions encountered during pre-sales engagements, drawn from Fusion SMB's documentation, knowledge base, and field experience.
Protocol & Compatibility
What SMB versions does Fusion SMB support?
Fusion SMB supports SMB 2.002, SMB 2.1, SMB 3.0, SMB 3.02, and SMB 3.1.1. SMB1 (CIFS) is deliberately not supported due to known security vulnerabilities.
Administrators can configure which dialects are exposed — either an explicit list or a maximum version — to meet security or compatibility requirements.
Does Fusion SMB support macOS clients?
Yes. Fusion SMB includes Apple Extensions support, which provides native macOS compatibility including server-side copy for macOS clients. Enable it with apple_extensions = true in the global configuration.
Known macOS limitations:
- Multichannel requires multiple adapters — Unlike Windows, the macOS SMB client does not create multiple TCP connections over a single network adapter. To benefit from multichannel on macOS, the client needs multiple physical adapters (e.g., wired + wireless, or multiple NICs). This limits single-adapter macOS clients to the throughput of a single core.
- Zero-copy read workaround — In some macOS workloads, disabling
vfs_zerocopy_read(set tofalse) on the share can improve performance. Test in your environment before deploying. - macOS SMB client regressions — Apple has historically introduced and fixed SMB client issues between OS releases. Tuxera works directly with Apple to address these, but recommend testing with each major macOS update.
macOS multichannel and zero-copy workarounds are from partner training sessions (Aaron Kennedy, Sep 2023). Confirm these limitations still apply with current macOS and Fusion SMB versions.
Does Fusion SMB support printer sharing?
Yes. Printers detected on the Linux server can be shared via SMB. Configure printer shares in the configuration file using the type = printer parameter.
Can Fusion SMB run alongside NFS?
Yes. Fusion SMB handles SMB protocol traffic on port 445 and can coexist with NFS and other file services on the same server. This is a common deployment pattern for environments that need both Windows and Linux/UNIX client access.
Does Fusion SMB support DFS (Distributed File System)?
Yes. DFS can be enabled globally and on a per-share basis. This allows Fusion SMB to participate in DFS namespaces.
What about SMB multichannel?
Fusion SMB supports multichannel connections, allowing clients to use multiple network interfaces simultaneously for increased throughput and resilience.
Security
How does Active Directory integration work?
Fusion SMB integrates with AD via SSSD and Kerberos. The server joins the domain using adcli, authenticates users via Kerberos, and resolves user/group information through LDAP. All standard AD trust types are supported — parent-child, tree-root, forest trusts, and external trusts.
Reference: Active Directory Integration on docs.tuxera.com
Does Fusion SMB support trusted domains?
Yes. Fusion SMB supports all Active Directory trust types. For trusted domains, it can:
- Authenticate users from trusted domains
- Append SIDs and names of trusted domains to the known list
- Resolve SID-to-UID for users and groups from trusted domains
The trust configuration is managed entirely in Active Directory — Fusion SMB respects whatever trusts AD defines.
Reference: KB: Trusted Domains on docs.tuxera.com
What encryption options are available?
- Encryption in transit — enable globally or per share (
encrypt_data = true) - Reject unencrypted access — force all clients to use encryption (
reject_unencrypted_access = true) - Message signing — configurable requirement (
require_message_signing = true)
Encryption requires SMB 3.0 or higher.
What authentication methods are supported?
| Method | Configuration |
|---|---|
| Active Directory | userdb_type = ad — Kerberos authentication via SSSD |
| LDAP | Direct LDAP integration for non-AD environments |
| File-backed database | userdb_type = text — local user database for standalone deployments |
| Guest/Anonymous | Configurable guest account access |
How are file permissions handled?
Fusion SMB offers four file security modes, configurable per share:
| Mode | Behavior |
|---|---|
| hybrid | ACLs stored in extended attributes, with POSIX fallback |
| windows | Full Windows ACL behavior (requires AD) |
| posix | Standard UNIX rwx permissions |
| none | No file-level checks — access governed by share permissions only |
ACL storage mechanisms include extended attributes (xattr:raw) and other formats, configurable per share.
Performance
Why is performance lower with Windows 11 24H2?
Windows 11 24H2 and Windows Server 2025 changed the default SMB signing behavior to always require signing. This is a Microsoft platform change, not specific to Fusion SMB, and affects all SMB servers.
Impact: SMB signing adds computational overhead to every message, reducing throughput.
Resolution: Disable SMB signing on the client via Group Policy if performance is prioritized. No changes are needed on the Fusion SMB server. Evaluate the security vs. performance trade-off for your environment.
Reference: KB: Windows 11 Performance on docs.tuxera.com
How does Fusion SMB achieve higher throughput than Samba?
Fusion SMB is the only multi-threaded SMB implementation for Linux. Where Samba uses a single thread per connection (typically maxing out around 2.5 GB/s), Fusion SMB's architecture fully utilizes modern multi-core CPUs, achieving throughputs up to 25 GB/s when network and storage permit.
Additional performance features include:
- Zero-copy I/O for read operations
- SMB Direct (RDMA) support for bypassing CPU in data transfers
- Configurable VFS thread pools per share
- File space preallocation for write-heavy workloads
- SMB 3.1.1 compression (LZ77)
What performance tuning is available?
Fusion SMB exposes extensive tuning parameters:
- Thread counts for transport (rx/tx), VFS data, and VFS metadata
- SMB2 credit limits and message size limits
- Zero-copy behavior per share
- Oplock strategies (full, read-only, disabled)
- Per-share VFS thread pools for workload isolation
- File preallocation thresholds
Reference: Performance Tuning on docs.tuxera.com
Deployment & Management
What Linux distributions are supported?
Ubuntu, Debian, RHEL, Rocky Linux, CentOS, AlmaLinux, and OpenSUSE Leap on x86_64, ARM64, and PowerPC64. Custom builds are available for unlisted distributions.
How is Fusion SMB configured?
Via an INI-format configuration file (/etc/tsmb.conf) with a [global] section and [share] sections. Configuration can also be managed at runtime using the tsmb-cfg CLI tool.
Starting the server with -p (persistent mode) automatically saves runtime changes to the config file.
Can shares be managed remotely via Windows?
Yes. Fusion SMB supports the Microsoft Management Console (MMC) snap-in for remote share management. This requires the IPC$ share to be enabled and administrative shares to be configured.
How does Fusion SMB start at boot?
Create a systemd service file pointing to /usr/sbin/tsmb-server and enable it with systemctl enable. A sample service file is provided in the documentation.
Can configuration changes be made without restarting?
Yes. When the server is running, use tsmb-cfg to add, update, or remove shares at runtime. Changes take effect immediately. Starting with -p flag makes runtime changes persistent across restarts.
Clustering & High Availability
What clustering topologies are supported?
- Active-passive — one active node, one standby, with floating IP failover
- Active-active — multiple active nodes with load balancing and shared FSA state via Corosync
What clustering software does Fusion SMB require?
Fusion SMB integrates with Corosync (for inter-node messaging) and Pacemaker (for resource management and failover), but does not mandate specific clustering software. Any solution that can manage IPs, storage mounts, and service lifecycle can work.
What happens to open files during failover?
With Continuous Availability (CA) enabled, the persistent file handle database allows clients to resume open files on the new node. TCP Tickle ACK triggers rapid reconnection without waiting for TCP timeout.
What shared file systems work with active-active?
Any clustered file system supporting concurrent read-write mounts: GlusterFS, WekaFS, CephFS, GPFS, GFS2, OCFS2, Lustre, among others.
For active-passive, any Linux file system works (ext4, XFS, ZFS, NTFS by Tuxera, etc.).
Licensing & Support
How is Fusion SMB licensed?
Licensing details are managed by the Sales team. Refer to Pricing & Licensing in the Sales track or contact your Tuxera account manager.
What support is available?
Tuxera provides comprehensive support backed by its partnership with Microsoft. Support includes documentation, training, and expert engineering assistance. Partners can contact support through the Tuxera Support Portal.
Next Steps
- Technical Overview — review the complete feature inventory
- PoC Guide — set up a proof-of-concept
- Full documentation at docs.tuxera.com