For a user to create, delete, or rename a file or a directory requires Write access to the parent directory that contains these files. Only the owner of a file (or the root user) can change permissions.
Permissions are based on the user IDs (UIDs) for the file Owner and group IDs (GIDs) for the primary group. Files have owner IDs and group owner IDs. To enable Unix access, the DR Series system supports three levels of users:
To enable Windows access, the DR Series system supports access control lists (ACLs) that contain zero or more access control entries (ACEs), and an empty ACE list grants all access requests. The Windows New Technology File System (NTFS) uses ACLs as part of the security descriptor (SD) process, which requires permissions to access such filesystem objects as files and directories. ACLs support two levels of users:
Both Owners and Groups have Security IDs (SIDs) that define and identify an object owner or the group owning an object. ACEs in an ACL consist of a SID, a specific permission that either allows or denies access and also defines which of the following inheritance settings apply:
Rapid NFS and Rapid CIFS enable write operation acceleration on clients that use DR replication and NFS or CIFS file system protocols. Similar to OST and RDS, these accelerators allow for better coordination and integration between DR Series system backup, restore, and optimized deduplication operations with Data Management Applications (DMAs) such as CommVault, EMC Networker, and Tivoli Storage Manager. For the current list of qualified DMAs, see the Dell DR Series System Interoperability Guide.
Rapid NFS is a new client file system type that ensures that only unique data is written to the DR Series system. It uses user space components and file system in user space (FUSE) to accomplish this. Metadata operations such as file creates and permission changes go through the standard NFS protocol, whereas write operations go through RDNFS.
Rapid NFS and Rapid CIFS require you to install a plug-in on the client or media server, depending on your DMA and configuration. For details, see the Configuring and Using Rapid NFS and Rapid CIFS chapter.
The DR Series system and backup application integration is done using DR Rapid plugins developed by Dell. Plugins allow backup application control over backup image creation, deletion, and duplication. They also allow deduplication and compression operations to happen on the client-side so that network traffic can be reduced.
DR Rapid allows the supported backup applications to communicate directly with the DR Series system and determine whether a specific chunk of data already exists on the system. If the data already exists, only the pointers need to be updated on the DR Series system, and the duplicate chunk of data does not need to be transferred to the system. This process provides two benefits: it improves the overall backup speed, and also reduces the network load.