[CentOS] DatOptic RAID Array >2TB?

Jim Perrin jperrin at gmail.com
Fri Jun 8 01:13:56 UTC 2007

On 6/7/07, Benjamin Karhan <simon at pop.psu.edu> wrote:
> i'm trying to set up a hardware RAID array (eRAID from DatOptic)
>    under CentOS.  we have two more of these arrays which have worked
>    very well for their purposes (backup and/or portable storage), but
>    neither of our older arrays exceeded the dreaded 2TB barrier
>    (one of them is, in fact, 2TB).

Some raid devices themselves have a 2TB limit, and you either have to
enable spanning on the raid card, or use the OS to work around this.

> the RAID array is the DatOptic eRAID, with 5 750GB disks in a
>    RAID-5 array.  the array itself seemed to have no problem
>    creating the ~3TB volume, but it does not detect as that
>    size when i hook it up.

You used parted and set the partition type as GPT right? If it's not
GPT, then you'll hit the 2TB limit with the filesystem.

>         Disk geometry for /dev/sda: 0.000-2097128.999 megabytes
>         Disk label type: gpt
>         Minor    Start       End     Filesystem  Name                  Flags

Yep, seems you're using GPT.

What filesystem are you using for this? I didn't see that informaiton
in the provided info, unless I overlooked it.

> it's important that we get full use of the array (1TB is a lot of
>    space to waste).
> anyone have any ideas, suggestions, comments, or criticisms?
> any help would be greatly appreciated...

Very much so. Worst case I'd say split it up into 1TB chunks and use
LVM to join them all.

During times of universal deceit, telling the truth becomes a revolutionary act.
George Orwell

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