[CentOS] Setting up large (12.5 TB) filesystem howto?
Neil Muller
neil at neologix.net
Fri Aug 28 13:13:42 UTC 2009
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
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