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Can I span a folder on the SD card on my Raspberry Pi with a folder on an attached USB device?

I'd like to basically extend the size of a directory by using an attached USB memory stick.

I'm running Debian wheezy.

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migrated from serverfault.com Mar 18 '13 at 23:41

This question came from our site for system and network administrators.

You're either wanting to simply mount that stick to the folder, or use unionfs. – Chris S Mar 18 '13 at 23:41
Do you want to choose which files go on which support, or do you want that to happen behind the scenes? What do you expect to happen if either the SD card or the USB stick breaks down? – Gilles Mar 18 '13 at 23:44
You could make them into an LVM volume, but that is kind of nonsense for removable media. – vonbrand Mar 19 '13 at 0:05
RAID and btrfs are also valid options, keep in mind that makes you very dependent of the reliability of both media devices and if one fails, all is basically lost. – David Kohen Mar 19 '13 at 7:07

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