Cloud Volumes Service shares file systems (volumes) to network-attached storage (NAS) clients. Such clients are usually virtual machines (VMs) running Windows or Linux operating systems, using the industry-standard Network File System (NFS) and Server Message Block (SMB) protocols.
Both NFS and SMB use a client-server model, in which a client (for example, a Windows VM) sends requests to a server (Cloud Volumes Service) to act on the file system. Such actions include creating or deleting files or folders, modifying files, and browsing and reading the files.
Volumes can be shared between many clients. Windows, Linux, and UNIX operating systems include built-in SMB and NFS client software.
NFS uses user IDs and group IDs, or Kerberos principals for Kerberized NFSv4. SMB uses security identifiers (SIDs) for Windows. Kerberos and SMB require access to Active Directory to look up names and security identifiers.
All file system objects are owned by a user (indicated by a user ID or security identifier) and access permission can be attached. For NFS, these are standard UNIX-style user and group permissions. NFSv4 also offers NFSv4 ACLs as an alternative method of managing access. SMB uses NTFS permissions.
To learn more about how NFS and SMB work, see Basics of NAS protocols.