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).

SanDisk Cruzer Titanium x6Can a software raid array of 6 usb flash drives perform well? Is it silly to even try? Well theres one way to find out.

Flash memory as a main storage medium is a relatively new phenomenon. Flash is known for its lack of seek time, so we wanted to see just how much bandwidth we could squeeze out of these devices over the USB bus.

It turns out that even with all of the limitations of the USB bus working against us we were still able to obtain some very good results at a very nice pricepoint.