It is necessary to take every possible step to speed up backups to reduce the impact on performance. Perhaps from this perspective, depending on the hardware or software used for backup, backup to disk will be faster or directly backup to other media such as tape or optical disc to write faster. It’s a common misconception that the backup to disk is always faster. With recording technology becomes better and better, it is not uncommon to see a large database of several hundred gigabytes in size up to get a parallel flow, the flow of some of the machines referred to some of the tapes in a few hours. In fact, for some configurations, the tape provides a higher speed in a controlled environment.
If there is a chance to meet the productivity in the real environment, you can backup to tape directly proves that much faster backup to disk. In fact, often limit the productivity of tape backup to hard disk, which rarely rises above the 8-10 MB / sec most database activity because you can not simply that the data to a tape drive to be written in the fastest time and read data from disk. Again, I have observed that 8-10 MB / sec in an environment where the disk subsystem using the latest technology, for example, fiber and communication channels to the controller fastSCSI and put this very well. Quite a number of environments, OLTP, where I / O channels are rare, and the reserves must compete with normal database operations, the read / write very random, and the disk drive will be limited to pass only 3-5 MB / sec.
However, this may not be true in any environment. Depending on various factors such as the type of backup media is currently using, whether the device is connected locally or remotely to a production machine, and a number of parallel backup streams that they can deal with it, and pass all the stream, and the transfer speed of the drive, they have devoted to you I / O changes to reserves, and so on, and a good backup disk or direct backup to tape may prove to be faster for you. If you write in a single stream to tape device networking products, chances are, you may backup to disk provides a higher speed than that. In any case, does not diminish the importance of backing up fast, and backup speed is not the main reason for this suggestion. In contrast, the speed of healing.
Once the file is available on disk, in the case of an accident database, and no need to restore from offline storage media, thus reducing the recovery time means. Most of the delay of the recovery does not occur during the actual act itself, but to restore the necessary files from the backup media today. Can be avoided if the backup file is now on the disk, and the delay is due to the high restoration time. This is the reason for each site 24/7, respectively, to maintain the most recent backup via the Internet.