Roadrunner SMB — Known Limitations
Last Updated: 2026-04-15
This document describes known limitations, constraints, and explicitly unsupported features in the current release. Read this before deploying for production use.
Deployment and Topology
Fixed cluster size
The Marketplace offering deploys a fixed 2–4 node cluster. Cluster size is controlled by AWS infrastructure (ASG/ECS); there are no scaling controls in the Admin UI.
Validated deployment range: 1–4 nodes. Deployments outside this range are not tested and not supported.
Minimum 2 Availability Zones required
Subnets must span at least 2 AZs. Single-AZ deployments are not supported.
Scaling is infrastructure-managed only
Cluster size changes are performed by updating CloudFormation parameters. There is no in-product resize capability.
No cross-region or DR support
Roadrunner SMB is a single-region deployment. Cross-region replication and disaster recovery configurations are not supported.
Active Directory
Single domain only
One Active Directory domain per deployment. Cross-domain trust scenarios are not supported.
Leave Domain not supported
Leaving the Active Directory domain from the Admin UI is not supported. To change domain membership, redeploy the appliance via CloudFormation.
Guest access not supported
All SMB access requires Active Directory authentication. Guest or anonymous access is not supported.
SMB Protocol Features
The following SMB features are not supported in the current release:
| Feature | Status |
|---|---|
| SMB Multichannel | Not supported |
| SMB Direct (RDMA) | Not supported |
| SMB Compression | Not supported |
| SMB Encryption (SMB-layer) | Not supported (network-layer encryption via TLS/VPN is supported) |
| Persistent Handles (SMB 3.x) | Not supported |
| Named Pipes / RPC Endpoints | Not supported (file sharing only) |
| DFS Namespaces | Not supported |
| Shadow Copies (VSS) | Not supported |
| Quotas | Not supported |
| File Change Notifications | Limited (standard SMB notify; not all change types) |
Networking
Admin UI transport
In Marketplace (multi-AZ) deployments, the Admin UI is served via the ALB on port 443 (HTTPS). The ALB terminates TLS; internal traffic from the ALB to RRSMB nodes on port 8888 is not encrypted.
In single-node / EasyButton mode, the Admin UI is served directly on port 8888 via the NLB without TLS termination.
Recommendation: restrict the AdminCidr security group to trusted networks and access the Admin UI only from within a VPN or AWS Direct Connect/private connectivity.
NLB DNS used for share paths
Shares are accessed via the NLB DNS name. Customers who require a custom DNS name should create a CNAME or alias record in their DNS pointing to the NLB DNS name.
Performance
EFS/NFS backend limitations
Roadrunner SMB stores share data on Amazon EFS (NFS). Some file operations have different semantics on NFS compared to a native NTFS filesystem:
$QUOTAvirtual file is not supported (EFS has no quota enforcement)- NULL DACL behavior differs from native NTFS
- Some timestamp precision differences may be observed
These are fundamental EFS/NFS backend constraints and are not correctable at the Samba configuration level.
No file data caching
File data read/write operations are not cached; performance depends on EFS throughput and latency. Use EFS Elastic throughput mode (default) for best performance.
Monitoring and Metrics
Cluster metrics are aggregated, not per-node
The Admin UI shows cluster-wide aggregate metrics collected across all active nodes. Per-node metric drilldown is available via the Prometheus endpoint on each node (port 9090 on the task ENI) for advanced diagnostics.
No external metrics integration
There is no built-in integration with Grafana, Datadog, CloudWatch Metrics, or other external platforms. Raw Prometheus metrics are exposed per-node on port 9090.
Admin UI Configuration
Some settings are environment-variable only
The following configuration items are only changeable via CloudFormation environment variables; they are not exposed in the Settings page:
- Container CPU/memory limits
- EFS throughput mode
- Log level (runtime override available via Logs page)
- CTDB tuning parameters
Software Updates
Updates require a CloudFormation stack update
There is no in-product auto-update mechanism. To update Roadrunner SMB, update the BackendImageUri CloudFormation parameter to the new image tag and run a stack update.
The update process performs a rolling node replacement, maintaining at least 2 of 3 nodes serving throughout.
Support
Support report required for assistance
When contacting support, generate a Support Report from the Admin UI Support page. First-line support requires the report to begin triage.
Early-customer support SLA
Initial response time: best effort within 1 business day. Formal SLA: to be published.