Why Network-Enabled Backup?
Most of us are familiar with direct-attached backup. In direct-attached backup, you connect a tape device to a NAS server using the SCSI interface and back up data from the server to the tape via SCSI.
Direct-attached backup has several disadvantages:
1. Every NAS server requires a dedicated tape device, significantly increasing the number of tape libraries your datacenter needs. The cost of tape libraries and the overhead needed to manage them are prohibitive.
2. In most situations, libraries dedicated to individual NAS servers may be underutilized. There is no way to "lend" the unused capacity of these tape libraries to those NAS servers that may need more backup capacity.
3. Tape libraries need more maintenance than NAS servers need. Bringing down and detaching a direct-attached SCSI tape library requires that the host NAS server is brought down as well, drastically lowering the uptime of the NAS server.
Network-enabled backup is the antithesis of direct-attached backup. It eliminates all significant problems related to direct-attached backup. If a SCSI backup device is network enabled, it makes it possible to send data via Ethernet to the backup device without direct attachment. In many ways, this is similar to the concept of network-enabling a printer. A network-enabled printer can be shared by every computer on the network, eliminating the need for a dedicated, locally attached printer per computer.
By network-enabling backup devices, you can share the backup devices among multiple NAS servers. Sharing reduces the number of backup devices needed, thereby reducing cost and maintenance issues. You don't need to buy a new backup device when you add a new NAS server or increase a NAS server's storage capacity.
Network-enabling backup devices also promotes pooling of backup devices to achieve a much higher cumulative backup speed. Pooling can shrink the backup windows dramatically.
Network-connected backup devices also eliminate the NAS downtime issues caused by direct-attached devices because removing devices on the network does not cause other devices or servers on the network to be brought down.
For a while, network-enabled backup solutions were proprietary to specific backup software vendors. Each vendor would have to integrate and maintain its solution with a myriad of NAS devices. Fortunately, an open-standard protocol for network backup has since been developed and embraced by the backup industry. This protocol is called Network Data Management Protocol (NDMP). The protocol allows backup and network-attached file server vendors to focus investment on functionality instead of excessive porting, and gives users an unprecedented level of choice and interoperability. As a result, NDMP is the best option for implementing a network-enabled backup solution.
Ways to Network-Enable Your NAS Backup
1. Using a NAS Server as a Backup Server
You can use one of your existing NDMP-capable NAS servers as a backup server. You can attach a local SCSI tape library to this backup NAS server and route backup data from all other NAS servers on the network to the backup NAS server. While this option preserves your investment in existing tape libraries, it brings down the performance of your backup NAS server drastically to a point that you may not be able to use the backup NAS server for anything other than backup serving. Considering the price you pay for a NAS server, this is a very expensive way to do network backup.
2. Buying a New Network-Capable Tape Library
You can also buy tape libraries that are already network enabled. This is a viable option if you are willing to throw away your existing SCSI tape libraries and buy new network-enabled tape libraries. Another point to consider is that because only one or two vendors sell network-enabled tape libraries, you could be locking in to a specific library vendor's offering, which may limit your choice of tape technologies and increase cost of ownership.
3. Using DinoStor TapeServer
The best way to network-enable your existing libraries, without obsolescing any existing library, drive, or network infrastructure, is the DinoStor TapeServer. The TapeServer is an affordable, easily manageable solution that can present any SCSI tape device on the Ethernet network, at gigabit speed, using NDMP.