Hey, im looking to make a RAID array on a raspberry pi, using a couple of cheap flash drives connected to a USB hub.

Now, I understand, the way disks are identified in linux are by UUID (Amongst other things), but flash disks dont have UUIDS.

I could use mdmadm to make a raid array using /dev/sdxx but what will happen upon reboot ? How can I be sure that the flash drives stay as in their respective /dev/sdx position as opposed to changing around?

Sorry if my terminology is a bit strange, but I hope you understand my predicament?

Well it is tricky

1. creation time : all drives partitions including usb flash , got UUID , check that using root
create raid using /dev/sdx names , wich actually writes UUID into matrix

If somehow drives seX names get mixed , no worry , coz mdadm is UUID based , not sdX

my server output

Now , lets get some details about mdadm sda1


Please observe that mdadm sda1 UUID is identical with the one reported by blkid.


Let's insert an USB flash and run fdisk -l just to see it's dev name
Ok , got my flash in , it is partitioned otherwise there is no UUID
see ? even USB flash got it's own UUID , which indeed differ from one machine to another , and differ even on same PC if repartitioning

Did once a raid 0 but cannot reach more than 40-50 MB/s even with 4 x kingston datatraveller 20Mb/s read, ,mainly coz USB 2.0 is limited to 480 Mb/s, but LED's light is great ,

1 members found this post helpful.

Ah cheers, I'll need to read up on it and start messing about with my own USB Raid array.