[CentOS] Setting up large (12.5 TB) filesystem howto?

[Neil Muller]

On 28/08/2009, at 10:59 PM, Jim Perrin wrote:

> On Fri, Aug 28, 2009 at 7:03 AM, Götz Reinicke -
> IT-Koordinator<goetz.reinicke at filmakademie.de> wrote:
>> Hi,
>>
>> I'm trying to set up an iscsi 12.5 TB storage for some data backup.
>>
>> Doing so, I had some difficulties to find the right tool, maybe it's
>> also a question of the system settings...
>>
>> The server is a 32Bit CentOS 5.3 with the recent updates. Ths iscsi
>> connection can be establised.
>>
>> fdisk and parted fail to create any information on the device or fail
>> completely.
>>
>> using the lvm tools (pvcreate, vgcreate, lvcreate), I could finaly
>> create a logical volume:
>>
>> lvdisplay /dev/VolGroup02/lvol0
>>  --- Logical volume ---
>>  LV Name                /dev/VolGroup02/lvol0
>>  VG Name                VolGroup02
>>  LV UUID                h7T6tD-JZw2-UEdb-q1ml-BDqp-9E0u-mAop6x
>>  LV Write Access        read/write
>>  LV Status              available
>>  # open                 0
>>  LV Size                12,73 TB
>>  Current LE             3337487
>>  Segments               1
>>  Allocation             inherit
>>  Read ahead sectors     auto
>>  - currently set to     256
>>  Block device           253:4
>>
>>
>> But, I can't create a filesystem on it:
>>
>> mkfs.ext3 -m 2 -j -O dir_index -v -b 4096 -L iscsi2lvol0
>> /dev/mapper/VolGroup02-lvol0
>
> You have to smack mkfs around a bit to get it to work.
> The incantations are listed here, along with the various limitations.
> The long and short of it is that you have to use -F to tell mkfs that
> you're really, REALLY sure.
> http://www.bofh-hunter.com/2008/02/11/large-filesystem-creation/
>


For a 4K block size I think the maximum ext3 filesystem size is 8TB.  
You may need to use an 8K block size which gives a maximum filesystem  
size of 16TB.

Neil