Debian root partition greater than 2TB

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QUESTION :

I have two internal hard drives: a 4TB drive and a 750GB drive. After selecting RAID0 and installing Debian (wheezy) to a single partition, I ran fdisk -l which reported that the size of my root partition (/dev/sda1) was 1.4T. So, I’ve got a couple of questions….

1) I know that fdisk only allows up to 2TB so even if my (4TB + 750GB) drive was being restricted to 2TB, what happened to the other 0.6TB? Remember, I installed everything to one partition.

2) My ultimate goal is to have everything on a single 4TB partition. I’ve read about parted but everything I read relates to partitioning and mounting a non-bootable partition. This doesn’t apply to me as I’m using a single partition which contains /boot. What are my options?

ANSWER :

Just to sum up what we came with in the comments, here is your problem :

You are doing stripping (alias RAID-0) over two drives :

  • a 4 TB one
  • a 750 GB one

The size used on every drive of a RAID0 array is equal to the size of its smallest drive. Thus your array wil be 2*750 GB = 1.5GB.
Removing a bit of overhead and GiB/GB confusion, this came up with a 1.4TB array.

From there your only option is to use your drives separatly (which you seem to be unable to do using your SAS card) or replace the small drive by a 4TB one.

Anyway, remember Stripping is unsafe as any drive failure will result in the loss of data stored on both disks, because any block of data is split between both drives.

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