Overview of Backup Technologies and Major Enterprise Backup Software

Backup refers to the process of copying all or part of data from production hosts to other storage media to prevent data loss caused by human error or system failures. Over time, several mainstream networking models have emerged, including Host, LAN, LAN‑free, Server‑free and Server‑less.

Host backup is the earliest method where data is copied directly from the production server to backup media; it offers fast transfer and simple management but lacks sharing capabilities for large‑scale environments.

LAN backup introduces backup clients on each production system and a central backup server that controls the process, solving the sharing issue but creating heavy dependence on network and server resources.

LAN‑free backup moves the data transfer responsibility to the production systems themselves, reducing load on the backup server while still imposing significant load on the production hosts.

Server‑free backup combines snapshot functionality of storage arrays with backup servers, creating near‑zero backup windows and eliminating impact on production systems.

Server‑less backup transfers data directly between source and target storage (e.g., between storage systems and tape libraries) using commands issued to the source, thereby minimizing server resource consumption and achieving high performance.

Server‑less implementations typically rely on SCSI‑3 Extend Copy or the NDMP protocol to move data without server involvement.

Major backup software

EMC offers NetWorker (pure software) and Avamar (appliance or virtual edition) focusing on data deduplication. Symantec provides NetBackup and Backup Exec, both pure software solutions. Commvault’s Simpana and IBM’s Tivoli Storage Manager (now IBM Spectrum Protect) also follow a pure‑software model.

NetWorker supports NAS NDMP backup, with data flowing from clients to storage servers and then to backup media. Avamar adds deduplication capabilities and can operate as an appliance or virtual edition using external storage.

Commvault Simpana consists of CommServe, Media Agent, and iDataAgent, handling data transfer from agents to media devices such as disks, tape libraries or network shares.

Symantec Backup Exec targets Windows environments with limited database support, while NetBackup is a cross‑platform, high‑end product supporting a wide range of operating systems, databases, and advanced backup methods (LAN‑free, SAN‑free, NDMP).

IBM Spectrum Protect (formerly TSM) provides enterprise‑grade data management, including backup, archive, space management and disaster recovery, using an agent‑server architecture similar to Backup Exec.

Backup software feature analysis

Backup stores data for recovery; archive moves infrequently accessed data to cheaper media for long‑term retention. Some products (e.g., NetWorker, Simpana, NetBackup, TSM) include both backup and archive functions, whereas Symantec Backup Exec requires a separate Enterprise Vault for archiving.

Data deduplication reduces storage consumption by eliminating redundant data blocks. NetWorker requires Avamar or Data Domain for deduplication, while Simpana, Backup Exec, NetBackup and TSM have built‑in deduplication.

All listed products support NDMP for NAS backup, providing vendor‑agnostic NAS integration.

In terms of OS compatibility, TSM, Simpana and NetBackup offer the broadest support; NetWorker follows, and Backup Exec supports the fewest platforms.

Maintainability varies: TSM has a complex installation, while other solutions are generally easier to manage.

NAS backup and NDMP technology

NDMP, originally developed by NetApp and Legato (acquired by EMC), enables NAS devices to send data directly to tape libraries or backup servers without a client agent. Versions 2‑way and 3‑way define different network topologies.

2‑way NDMP connects the backup medium directly to the NAS, allowing data to flow straight from NAS to tape, improving performance but limiting tape library sharing to a single NAS.

3‑way NDMP introduces a dedicated backup network, enabling multiple NAS devices to share a tape library, though performance depends on network bandwidth.

Remote NDMP places the backup software between NAS and tape library, reducing NAS requirements and allowing shared tape resources, at the cost of increased network traffic and server load.

The accompanying diagrams (preserved from the original source) illustrate each topology and the trade‑offs involved.

Choosing the appropriate backup architecture depends on specific workload, performance requirements, and resource constraints.