Re: [opensuse] Use entire disk, and not a partition K.R. Foley wrote:
> Carlos E. R. wrote:
>>
>> The Wednesday 2008-02-13 at 13:51 +0200, Dirk Moolman wrote:
>>
>>
>>> Sorry, let me explain.
>>> We are using Oracle.  Oracle uses filesystems to create datafiles in,
>>> for example it will create files like:
>>> /oradata01/system01.dbf
>>> /oradata02/users01.dbf
>>
>>> Now if /oradata02 (a new filesystem I created) points to the device
>>> /dev/sda, instead of /dev/sda1 (a partition on sda), will this be a
>>> problem ?
> 
> I don't believe you can do this. I may be wrong but I believe you will
> need to create a single partition /dev/sda1 that encompasses the entire
> disk and use that.
> 
>> As far as I know, which isn't that much, there should be no problem. I
>> assume the space is initialized (mkfs)? You can test it: write a file
>> using the entire space in the disk (dd if=/dev/null of=...), check the
>> kernel log.
>>
>> It is also possible to write a single file to a device, without
>> filesystem (raw). I understand some databases did/do that. Being a
>> entire device there is no problem with partition limits and overwriting
>> another partition space, and it is supposed to be faster.
> 
> As for raw devices, I believe you can use the raw command to bind a raw
> device to a disk partition. The speed improvement is not due to the
> partition structure but the raw construct. The database engine is free
> to handle the I/O with the device rather than having to deal with the
> inefficiencies/help of the filesystem.

Oracle expects a raw block device (such as a disk drive),
not a raw character device, so there is no need to use
the raw command -- that will just slow things down


