Alternatives for Protecting NAS Data with TSM

Answer

Tivoli Storage Manager supports the following methods for backup and recovery of data on NAS devices.

One approach is to use a TSM backup-archive client to back up and restore data, by using CIFS or NFS to access files from the backup-archive client. Data can be stored on the TSM server with file-level granularity using progressive-incremental backup. The data is stored in the TSM storage hierarchy and can be migrated, reclaimed, and backed up to a copy storage pool. However, this approach introduces overhead for accessing individual files by the TSM client, requires data flow over a network and through the TSM client, requires data flow through the TSM server unless a LAN-free configuration is used, and may not preserve access-control lists because of limitations in the methods used for accessing files.

A variation on the above approach is to use a TSM backup-archive client running on the NAS device, provided that the NAS operating system allows external programs. This method avoids the overhead of CIFS or NFS. Data can be stored on the TSM server with file-level granularity using progressive-incremental backup. The data is stored in the TSM storage hierarchy and can be migrated, reclaimed, and backed up to a copy storage pool. However, this approach requires data flow through the TSM client. This method also requires data flow over a network and through the TSM server unless a LAN-free configuration is used.

Another method is to use the support for Network Data Management Protocol (NDMP) provided in Tivoli Storage Manager. File systems are backed up as full images (all files) or differential images (all files that have changed since the last full backup). Backed up images are stored on a tape device that is accessed by the NAS file server. This method provides high performance and scalability because there is no data flow over a network or through a TSM client or server. Data backed up to TSM using NDMP cannot be migrated, reclaimed, or backed up to a copy storage pool.