Re: [opensuse] Use entire disk, and not a partition Carlos E. R. wrote:
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> The Wednesday 2008-02-13 at 13:51 +0200, Dirk Moolman wrote:
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>>
>> 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 ?
> 
> 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.

As I recall, Oracle gets even better performance if you just
use a raw disk partition -- it is capable of managing block
placement on a raw disk, and gets much better perfomance than
by using the disk space through a filesystem driver.

That being said, if he decides to use the "whole disk" which
includes the 1 or 2 blocks normally reserved for the partition
table as part of his raw block device, he's just begging for
data loss if the disk is ever removed from the system and
put in another for some reason (hey! this partition table
makes no sense -- that must be the problem -- I'll remake
the first partition to use the whole disk...and wham, the
first 512 - 1024 bytes are overwritten).

> 
> 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.
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