# Flash Drive RAID



## Disparia (Feb 5, 2010)

When you have some old flash drives and nothing better to do, RAID them!

Going through my desk I found four 1GB flash drives, one I bought several years ago and the other three received at various computer conventions. They haven't seen much use as I have larger/faster drives.

Linux Software RAID will be used as it will allow a setup such as this with no fuss (I'm looking at you Windows ). Since I have a CentOS 5.4 disc on my desk, it's going to be the distro of choice tonight.


Testbed:

Celeron 2.8Ghz
MSI 945GM3
1GB DDR533


The Drives:








Setup #1

100MB /boot, ~3.5GB RAID-0, with remaining space on drives used for swap.

Setup took forever. I switched back over to my other box, watched a couple shows on Hulu, switched back, and it still took 20 minutes past that. Watching the activity lights on the drives I noticed that they would all blink for awhile, then three of them would stop. The lone active drive had a write speed so slow that it took *seconds* for it to catch up! Ugh. After reaching the desktop I found that the overall feel was ok, but because of 'that drive' everything would freeze until it finished writing. This happened a couple times every minute, so only one quick test will be done.

hdparm read = 46.7MB/s. Yay. Reboot, reformat, reinstall.


Setup #2

Slow drive = 100MB /boot, rest as swap.
Others = ~3GB RAID-0 array for /.

Installation on the three 'speedy' drives went much more quickly, about a quarter of the time. Desktop feel was again decent, but luckily no freezes. The numbers!

hdparm read = 43.6MB/s.
bonnie++ write = 6.7MB/s.

With writes like that you don't want to be doing too much at once. Yum download/install? Let it finish as web browsing was out of the question. But even when browsing was done alone it could be a stop and go event on picture heavy page.

While this particular setup doesn't provide the performance one would desired, it does give proof of concept to using cheap flash drives. Want that no-wires look and don't mind riding dirty? A 4-pack of 4GB sticks can be had for $33. Possible applications? For me it would be terminals around the house and I'd love to try to build a DIY tablet. That is, until direct-plug SSD's become cheaper (I'm looking at you SuperTalent and Apacer).


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## mlee49 (Feb 5, 2010)

I don't mind riding dirty, gather up a bunch of old flash drives for a cheap hdd solution.

What about using SD cards in the same manner?

And isn't using Flash Memory more prone to failure?  More use degrating overall preoformance?


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## Disparia (Feb 5, 2010)

The quality of flash used in these drives isn't as high as what you'll find in SSD's and there's probably no wear leveling, so yes, it wouldn't have the same longevity.

That's why I thinking terms, tablets, and perhaps folders/crunchers (though they don't need as much space, speed). The main purpose of the first two would be web, video (from a network share), and other such things. A disk dies, not a big deal.


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## xrealm20 (Feb 5, 2010)

Interesting concept - I know most of the new HP DL360's and DL380's - the G6 series, have an internal usb port for booting off of a flash device for a primary os.  Kinda cool.  

Might have to check this out with my test rig.


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## Disparia (Feb 5, 2010)

Supermicro has started adding ports to their boards as well.






No accidental drive pulls!


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