Shared FileSystem
The Shared Filesystem service in Zergaw CloudStack provides a scalable, persistent, and concurrent data repository that can be accessed simultaneously by multiple Virtual Machines (VMs) within the same network. This service is distinct from the primary storage used for VM root and data volumes (which are typically Block Storage) and is vital for collaborative and high-availability workloads.
Key Concepts
| Term | Description |
|---|---|
| Provider | The underlying technology providing the file system (e.g., NFS). |
| Mount Path | The specific network address (IP:/export/path) used by the VMs to connect and mount the filesystem. |
| Concurrency | The ability for multiple VMs to read and write to the same files at the same time, managed by the underlying file system protocol. |
| Protocol | Access is typically granted using standard file protocols like NFS (Network File System). |
How it Differs from Other Storage
| Storage Type | Primary Purpose | Sharing Capability | Access Protocol |
|---|---|---|---|
| Root/Data Volumes | Host operating system and application data (Block Storage). | Single-VM exclusive access (can be detached and reattached). | Block-level (iSCSI, Fibre Channel, RBD). |
| Object Storage | Unstructured data, media, backups (flat architecture). | Highly scalable access via HTTP API. | API-level (S3/HTTP). |
| Shared Filesystem | Collaborative content, application binaries, home directories. | Concurrent access by multiple VMs via a network mount point. | File-level (NFS, SMB). |
Core Use Cases
The Shared Filesystem is essential for architectures where data integrity and accessibility across nodes is mandatory:
- High Availability (HA) Clusters: Applications (like web servers or application servers) running across two or more VMs can access the same configuration files and application binaries simultaneously, ensuring service continuity if one VM fails.
- Web Content Management: Serving static web assets, user-uploaded files, and content libraries that must be visible immediately to all VMs in a load-balanced web farm.
- Application Installation: Storing common application packages or code repositories that need to be mounted quickly by development or build environments.
- User Home Directories: In VDI (Virtual Desktop Infrastructure) deployments, this storage provides a centralized location for user profiles and data.
Configuration and Access Flow
- Filesystem Creation: A user or project provisions a Shared Filesystem, defining its size and attaching it to a specific Virtual Network.
- VM Access: Once provisioned, the network path (
/mnt/share-name) is provided. The user must then manually mount this path from within their Guest VM using standard Linux or Windows mount commands (e.g.,mount -t nfs <IP>:/path /mnt/local). - Network Dependency: The Shared Filesystem can only be accessed by VMs attached to the same Virtual Network to which the filesystem was provisioned.