Sanitizing data from storage media is a critical component of data management, especially for governments and the enterprise. Sanitization is well-understood for traditional magnetic storage, such as hard drives and tapes. Newer Solid State Disks (SSDs), however, have a much different internal architecture, so it is unclear whether what has worked on magnetic media will work on SSDs as well.
At the Non-volatile Systems Laboratory we have designed a procedure to bypass the flash translation layer (FTL) on SSDs and directly access the raw NAND flash chips to audit the success of any given sanitization technique. Our results show that naïvely applying techniques designed for sanitizing hard drives on SSDs, such as overwriting and using built-in secure erase commands is unreliable and sometimes results in all the data remaining intact. Furthermore, our results also show that sanitizing single files on an SSD is much more difficult than on a traditional hard drive. We are working on designing new FTLs that correct these issues and also exploit properties of flash memory to maintain performance while sanitizing the flash drive.
We are actively seeking industrial partners for this project who can assist us in identifying parameters critical to particular applications and in acquiring small quantities of solid state disks for testing.
Individual file sanitization techniques, all of which failed and left at least 10MB of a 1000MB file. Auditing of several-built in sanitization commands, showing several failures.
- Reliably Erasing Data from Flash-Based Solid State Drives, , To Appear: 9th USENIX Conference on File and Storage Technologies (FAST '11), 2011.
- SAFE: Fast, Verifiable Sanitization for SSDs, , Unviersity of California, San Diego Computer Science amp; Engineering technical report cs2011-0963.
Sunday, 20 February 2011
Non-Volatile Systems Laboratory