Here are the main AWS FSx alternatives for shared file storage, depending on your use case:

1) Amazon EFS (Elastic File System)

Best if you want a fully managed shared NFS file system for Linux workloads.

• Protocol: NFSv4.1
• Good for: EC2, ECS, EKS, Lambda, shared app data, home directories
• Pros: Fully managed, elastic, regional, multi-AZ, simple to use
• Cons: Not ideal for Windows SMB workloads or very high-performance block-style needs

Use when: You need a shared POSIX-compatible file system and want the simplest AWS-native option.

---

2) Amazon S3 + file gateway / app redesign

Best if your “shared storage” is more about objects/files than a traditional file system.

• Options:
  • Amazon S3 directly
  • AWS Storage Gateway (File Gateway) to present S3 as NFS/SMB
• Good for: Backups, media, static content, archives, durable shared content
• Pros: Very scalable, durable, low cost
• Cons: Not a true file system; semantics and performance differ from NFS/SMB

Use when: You can tolerate object storage semantics or only need file-like access.

---

3) Self-managed NFS on EC2

Best if you need full control or specific filesystem behavior.

• Examples: Linux EC2 instance(s) running NFS server
• Good for: Custom tuning, legacy apps, specialized requirements
• Pros: Flexible, can be cheaper for small setups
• Cons: You manage patching, HA, backups, failover, scaling

Use when: Managed services don’t meet your requirements and you can operate it yourself.

---

4) Self-managed SMB/CIFS on EC2 (e.g., Windows File Server or Samba)

Best for Windows/shared SMB access without using FSx for Windows File Server.

• Good for: SMB shares, Windows apps, cross-platform SMB access
• Pros: Control over configuration
• Cons: Operational overhead, clustering/failover complexity

Use when: You need SMB but want to avoid FSx, and you’re okay managing Windows/Linux servers.

---

5) Amazon EBS shared indirectly via clustering

Not a shared filesystem by itself, but can be part of a shared-storage design.

• Approach: EBS attached to one EC2 instance or used with clustered filesystems
• Good for: High performance, single-writer workloads, clustered solutions
• Pros: Fast, low-latency
• Cons: Not natively shared across multiple instances; more complex

Use when: You need performance and can architect around single-writer or clustering.

---

6) Third-party shared file storage in AWS Marketplace

If you need advanced features similar to enterprise NAS.

• Examples: NetApp ONTAP, Dell/PowerScale, Qumulo, etc.
• Good for: Enterprise NAS features, snapshots, replication, tiering
• Pros: Rich feature set, often supports NFS/SMB
• Cons: Licensing cost, complexity

Use when: You need enterprise NAS capabilities beyond native AWS services.

---

Quick recommendation

• Linux shared file storage: Amazon EFS
• Windows SMB shares: FSx for Windows is usually the AWS-native choice; if avoiding FSx, use SMB on EC2 or a third-party NAS
• Object-style shared data: Amazon S3
• Custom/self-managed: NFS/SMB on EC2
• Enterprise NAS features: Marketplace appliances

If you want, I can also give you a comparison table of FSx vs EFS vs S3 vs self-managed NFS/SMB for cost, performance, and operations.