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> Concatenate block devices, Combine two "hard drives" into one
fa2k
 Posted: Oct 23 2013, 03:47 PM
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Hi, I need to access a 4TB SATA drive from a laptop, and bought a USB-based dock for hard drives. It doesn't seem to support 4TB drives, and presents two block devices of approximately 2 TB, sdb and sdc. The drive is already formatted with a GPT and one large ~4 TB partition, and I need to access data on this.

Is there any way to combine the two block devices sdb and sdc into one virtual block device which contains the data from sdb followed by sdc? No metadata must be added, obviously. I'm thinking of something like Device Mapper, but I don't know a lot about it. (I don't have enough local storage to copy the data to a file, even with compression)
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fa2k
 Posted: Oct 23 2013, 05:45 PM
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Yes! this worked (for future reference)
CODE
mdadm --build /dev/md0 --level=linear --raid-devices=2 /dev/sdc /dev/sdd
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tux99
 Posted: Oct 24 2013, 08:52 PM
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An alternative that I have been using without problems for the last 3 years (therefore IMHO it's stable and reliable) is to use mhddfs, you can find it packaged up for EL6 in my repo.
https://romanrm.net/mhddfs

QUOTE
mhddfs is a FUSE filesystem module which allows to combine several smaller filesystems into one big “virtual” one, which will contain all the files from all its members, and all their free space. Even better, unlike other similar modules (unionfs?), this one does not limit the ablility to add new files on the combined filesystem and intellegently manages, where those files will be placed.


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My personal SL6 repository, specialized in audio/video software: http://pkgrepo.linuxtech.net/el6/
(can be used together with EPEL and ELRepo repositories) - repository mirror: http://linuxsoft.cern.ch/linuxtech/el6/
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