Veritas Access Appliance Administrator's Guide
- Section I. Introducing Access Appliance
- Section II. Configuring Access Appliance
- Managing users
- Configuring the network
- Configuring authentication services
- Configuring user authentication using digital certificates or smart cards
- Section III. Managing Access Appliance storage
- Configuring storage
- Managing disks
- Access Appliance as an iSCSI target
- Configuring storage
- Section IV. Managing Access Appliance file access services
- Configuring the NFS server
- Setting up Kerberos authentication for NFS clients
- Using Access Appliance as a CIFS server
- About configuring CIFS for Active Directory (AD) domain mode
- About setting trusted domains
- About managing home directories
- About CIFS clustering modes
- About migrating CIFS shares and home directories
- About managing local users and groups
- Using Access Appliance as an Object Store server
- Configuring the NFS server
- Section V. Managing Access Appliance security
- Section VI. Monitoring and troubleshooting
- Configuring event notifications and audit logs
- About alert management
- Appliance log files
- Configuring event notifications and audit logs
- Section VII. Provisioning and managing Access Appliance file systems
- Creating and maintaining file systems
- Considerations for creating a file system
- About managing application I/O workloads using maximum IOPS settings
- Modifying a file system
- Managing a file system
- Creating and maintaining file systems
- Section VIII. Provisioning and managing Access Appliance shares
- Creating shares for applications
- Creating and maintaining NFS shares
- About the NFS shares
- Creating and maintaining CIFS shares
- About the CIFS shares
- About managing CIFS shares for Enterprise Vault
- Integrating Access Appliance with Data Insight
- Section IX. Managing Access Appliance storage services
- Configuring episodic replication
- Episodic replication job failover and failback
- Configuring continuous replication
- How Access Appliance continuous replication works
- Continuous replication failover and failback
- Using snapshots
- Using instant rollbacks
- Configuring episodic replication
- Section X. Reference
How Access Appliance Replication works
Access Appliance Replication is an incremental file-level replication service that runs on top of the Cluster File System that is used by Access Appliance which is, in turn, based on the Veritas File System (VxFS). Access Appliance Replication uses two file system specific features: File Change Log (FCL) and Storage Checkpoint services, to retrieve file changes between replication periods.
For a given period, the FCL records every change that is made to the file system. By scanning the FCL, Access Appliance Replication quickly identifies the file(s) that have changed and generates the modified file list. This list prevents the expensive file system scanning that is normally associated with file-based replication, and which typically results in sub-optimal performance.
Next, Access Appliance Replication uses VxFS Storage Checkpoint's metadata comparison feature to retrieve the modified extent list of each changed file. It does not need to access the file data. Access Appliance Replication replicates files data, metadata, access control lists (ACLs), extended attributes, and modification timestamp changes. It does not replicate any changes made to access time and change time.
The Access Appliance Replication transport layer works with and interfaces to the well-known rsync remote file synchronization tool. Using this existing network transportation program makes the network configuration much easier in the enterprise domain: the Secure Socket Shell (SSH) port (22) required by rsync is opened by default on almost all enterprise firewalls. rsync is also a reliable solution for a low bandwidth or unreliable link environment.
Note:
Access Appliance uses the rsync protocol to provide transportation of Access Appliance Replication encapsulated files. The use of rsync is not exposed in Access Appliance, and cannot be administered outside of the Access Appliance Replication feature set.