Trying to mount 13 Tb disk on RedHat system.

[Nigel Wade]

Margaret Doll wrote:
> We got to create the 13 Tb partition on the  aux  disk on the RedHat 
> system by using parted, but then mkfs.ext3 doesn't work on any partition 
> larger than 2 Tb.

It should do. I have 6 and 7.8TB filesystems. What version of RH are you 
running? I suppose there may be limitations on some of the kernels, I am running 
64bit RHEL 4. However, I think there is limitation of 8TB for ext2/3 on systems 
which have a max. block/page size of 4kb. You need 8kb blocks/pages to get to 
16TB, or a different filesystem type and it's unlikely your system can handle 
that. Do you know what the max. page size if for your system?

> 
> If we split the aux disk into 2 Tb partitions, I understand from 
> http://www.linuxnix.com/2009/04/logical-volume-manager-lvm-in-redhat.html
> that we use fdisk to  change the partition type to  83 Linux LVM.  
> Unfortunately fdisk will only see the first 2 Tb partition, so we can't 
> create a LVM
> of the partitions.

If you want to go this way create individual LUNs on your RAID. There is nothing 
to be gained by partitioning the RAID. You can join the LUNs using LVM. That 
would enable you to create an LVM of 13TB, but you've gained nothing over using 
the bare device. You don't need a partition table on a device, you can create a 
filesystem on the entire device, /dev/sdc for example, rather than /dev/sdc1 etc.

> 
> We went back to parted and created one 13 Tb partition.  Then inside  
> parted, we used
> 
> mkfs 0 ext3
> 
> The program said  that ext3  was not supported in this version of 
> parted, but ext2 was.  I oked, ext2.
> Inside parted
> 
> (parted) print
> 
> Model: IFT A16F-G2430 (scsi)
> Disk /dev/sdc: 13.0TB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
> 
> Number  Start   End     Size    File system  Name     Flags
>  1      17.4kB  13.0TB  13.0TB  ext3         primary
> 
> the partition is  labeled as a ext3 file system.
> 
> Our 13 Tb partition was added to /etc/fstab as a ext3  filesystem and 
> mounted on  the system.
> 
> "df -h" though lists it as a 1.8 Tb system.
> 
> /dev/sdc1             1.8T  196M  1.7T   1% /m3team


Did you actually create a filesystem on that 13TB partition? Or did you just use 
the filesystem which you had already created previously when the partition was 
only 2TB? I'd be interested to know what mkfs said when you asked it to create a 
13TB filesystem, for example what block size did it set.

What does 'dumpe2fs /dev/sdc1' show?

-- 
Nigel Wade, System Administrator, Space Plasma Physics Group,
             University of Leicester, Leicester, LE1 7RH, UK
E-mail :    nmw at ion.le.ac.uk
Phone :     +44 (0)116 2523548, Fax : +44 (0)116 2523555