Flash devices operating in tandemRecently, we did some speed tests on running USB flash drives in RAID0 (see 6x USB Flash Drive Raid). The results of the tests were promising enough to warrant booting from the raid and using it as a root filesystem.

The problem is that booting from USB is a little hard, booting from raid is harder, but booting from USB raid is harder still. Googling around showed no results for any poor souls dumb enough to have tried, although we know you are out there.

We must work around our flash array's three main flaws:

1. Total disk space is limited (12GB in our raid)
2. Write speeds are not as fast as a typical modern hard drive write. In particular this causes fsync to be slow on most filesystems.
3. The bios ordering and linux device letters of the flash drives change at random (when we physically move them around).