The term flape stands for flash plus tape and describes the process of using tape media and flash storage to improve the data backup process. Tape continues to be the most cost-effective media for long-term data retention, including backups. The areal density (or amount of data per square inch of tape) has steadily increased over time, allowing standards like LTO to achieve a roadmap of tape media capacity that currently stands at 6 TB per cartridge raw. This is a 60-time increase from the first cartridges produced in 2000 with the same original form factor.
The drawback to tape is the serial nature of data access. Content on tape can only be read or written in a sequential format by spooling the tape to the position in which data is to be read or written.
In contrast to disk, where access times are measured in milliseconds, tape access times can be seconds or minutes long. The result is that serial access can be good -- streaming speed for LTO-7 is approximately 300 MBps -- whereas timely random access is almost impossible to achieve.
Flape uses fast NAND flash technology as a high-speed cache that buffers data read from and written to tape. Flash is the perfect random access media, with no performance impact for even 100% random I/O activity. The mixture of flash and intelligent software algorithms, including IBM's Linear Tape File System tape format, allows the flape combination to make writing to tape much more efficient than what could be achieved with tape alone. Data can either be buffered in flash for sequential writing to tape or prefetched from tape to anticipate read requests (like restoring a backup).
Flash improvements will play a key role
The future of flash plus tape lies in how flash technology will continue to improve over time. Flash media prices per gigabyte of storage are declining in a trend similar to that of hard disks, with new devices reaching multi-terabyte capacities. These improvements are being delivered through technologies like 3D NAND, triple-level cell and, in the future, quad-level cell devices.
The upshot is that flape systems will provide greater amounts of flash capacity per terabyte of tape capacity at a practical cost point. With faster processors and cheaper system memory, the result will be more efficient, less expensive offerings for storing large volumes of data on tape. With flash capacities set to exceed disk capacities, this could make disk-based backup systems much less attractive for customers with large volumes of data to store.
Flash plus tape will continue to serve archive and backup requests with the potential to provide more search and index capabilities as more data becomes cached at the front end of flape systems.
Users see value in LTFS and flape systems
Archiving heads toward open approaches, such as flash plus tape
Explore tape archiving with disk or flash