Two of the biggest advantages of server-free backup are server/LAN resource savings and the ability to leverage SAN technology and application investments.
BY MICHAEL ADAMS
While server-free, or "serverless," backup (moving data directly from disk to tape without going back through the host server) promises to deliver reduced impact to IT storage infrastructures and cost of ownership improvements, what does this actually mean? How will users be able to explain what the real benefits of this technology will be? And more importantly, how will server-free technology lead to a reduced bottom line from both a business and IT point of view? To answer these questions, let's take a look at two of the largest benefits associated with server-free backup:
- Server and LAN resource savings (reduced CPU, I/O, memory, and network impact) and
- Leveraging storage area network (SAN) technology and application investment.
Server/lan Resource Savings
In most LAN-based backup architectures, data flows from each server being backed up across the LAN to a dedicated backup server. This means that each server being backed up is involved in the backup process. While previous business models could handle this type of processing during the backup window (time allocated for backup operations), today's global corporations cannot experience this type of impact on their critical servers. Resources such as CPU, I/O, memory, and the network must be devoted to business transactions and not backup. Backup is important, but it must consume as few of these resources as possible.
Figure 1: Graphs show the system performance impact of a standard backup (top) and a server-free backup (bottom).
In addition, some corporations have adopted the model of spending more IT dollars to purchase additional servers for backups. However, IT budgets (purchasing dollars for hardware, software, or human resources) are not keeping pace with data growth, and crucial dollars are being lost to the purchase of additional hardware. While this might fix the problem initially, data growth is not going away and most likely will strike an IT department repeatedly. The scalability of this model is flawed. IT departments need to make their dollars go further.
How users will benefit
The biggest benefit associated with server-free backup technology is the reduced impact or reduction in the "backup footprint" at the host server level. The use of snapshot technology combined with direct disk-to-tape data movement significantly reduces CPU, I/O, and memory overhead in the host server. It will also place fewer burdens on the network.
Figure 1 indicates how dramatic this reduction can be. On the top, the performance meter shows the impact a standard Oracle backup can have on a system. While this is justifiable for some IT operations, global enterprises cannot afford this kind of impact on their systems. On the bottom, there is only a small impact on a server-free Oracle backup. The same statistics (CPU, I/O, memory, and network) are dramatically lowered to the point of almost being non-existent. Testing has also shown that these results improve as the data size increases.
Figure 2: In a server-free backup operation, data moves from disk to tape across a dedicated network without host server involvement.
In addition, being able to deliver more performance out of a single backup server will also enable IT departments to reduce capital expenditures on additional server hardware. This is made possible by the fact that server-free technology requires that a server only receives and passes a small amount of metadata to a third-party copy engine instead of handling all the backup data by itself.
Leverage Sans, App Investments
SAN technology has become a reality for some environments with cutting-edge storage needs. This architecture has provided server/storage consolidation, improved performance/distance/connectivity through Fibre Channel, and most likely has added to the backup/restore capabilities for IT departments. For these types of environments, many users are now left with the question of what else they can do with SAN architectures.
Applications such as Microsoft Exchange or Oracle Financials have become mission-critical to IT environments. Although techniques such as hot backups have been developed and serve as the best solution to back up these applications, enterprise environments need more-advanced techniques when it comes to backup and recovery. In addition, users may not be aware that application vendors must enable their APIs so that third-party vendors can make server-free technology happen for these applications. Without enabling the application APIs for advanced functionality, server-free backup is not possible.
How users will benefit
Server-free backups provide a new level of functionality in a SAN environment beyond what is currently available. The movement of data across a dedicated network without host server involvement can help leverage SAN infrastructure expenses beyond LAN-free backup (see Figure 2). It is a logical progression that will help justify the high per-port costs of SAN hardware. In addition, it will maximize the use of SAN components.
Applications that can be backed up server-free will also provide data protection without producing a major impact on users trying to access these systems. This is emphasized in the phrase "zero-downtime" backups. Once a snapshot is created, the application can be released and continue with its transactions. Applications are no longer involved in the backup process. Again, this takes hot backups a step further and translates to the increased productivity of the application servers while also providing data protection. While it is true that application vendors must enable APIs to make this functionality available, most application vendors either have this technology or will provide it in the near future.
As is the case with any cutting-edge technology, server-free technology will continue to improve in terms of performance and flexibility (e.g., operating system platforms and multiple snapshot offerings). This does not make the technology any less viable today, given the right environment. While server-free technology is not for every IT shop, its benefits for customers with expanding backup needs cannot be overlooked.
Michael Adams is a product marketing manager at Veritas Software (www.veritas.com) in Mountain View, CA. He can be reached at firstname.lastname@example.org.