I'm building a hybrid app that has VMs on-prem and workloads in cloud. What file storage fits?

For a hybrid app with on-prem VMs and cloud workloads, the best fit is usually a shared file storage service that works over standard protocols and can be accessed from both environments.

Best fit options

1) Cloud file storage with SMB/NFS support

If you want one central file share that both on-prem and cloud workloads can use:

• Azure Files — good if you’re in Microsoft/Azure ecosystem
  • Supports SMB and NFS
  • Can be mounted by VMs and some app servers
  • Works well with identity integration and hybrid access
• AWS EFS / FSx
  • EFS for Linux/NFS workloads
  • FSx for Windows File Server for SMB/Windows-heavy environments
• Google Filestore
  • NFS-based, more for GCP-native Linux workloads

What’s usually best for hybrid

If you need:

• Windows VMs / .NET apps / SMB shares → Azure Files or FSx for Windows
• Linux workloads / POSIX-style file access → NFS-based storage like Azure Files NFS, EFS, or Filestore
• Mixed on-prem + cloud access to the same file share → a managed cloud file service + site-to-site VPN or ExpressRoute/Direct Connect is often the simplest approach

Things to watch for

• Latency: file shares are sensitive to network delay, so hybrid access can feel slower than local disk.
• Caching/sync: if the app needs offline/local performance on-prem, you may want a sync/caching layer instead of direct shared storage.
• Protocol compatibility: SMB vs NFS matters a lot.
• Access control: ensure identity/auth works across both environments.
• Data residency/compliance: may affect whether cloud-hosted file storage is acceptable.

Rule of thumb

• If you want shared file access across on-prem and cloud: managed cloud file storage with SMB/NFS
• If you want very low latency on-prem and occasional cloud access: consider file sync/replication or keeping primary storage on-prem with cloud replication

If you tell me:

1. Azure / AWS / GCP / vendor-neutral,
2. Windows or Linux, and
3. whether you need shared file access or object storage,

I can recommend the exact service.