[CentOS] CentOS 6.4 Installation on Dell R720

[Dennis Jacobfeuerborn]

On 09.10.2013 10:39, Kaushal Shriyan wrote:
> On Tue, Oct 8, 2013 at 3:45 PM, Dennis Jacobfeuerborn <dennisml at conversis.de
>> wrote:
>
>> On 08.10.2013 07:25, Kaushal Shriyan wrote:
>>> Hi,
>>>
>>> I am planning to install CentOS 6.4 on Dell R720 which has hardware raid
>>> card and 6 hard disk slots available.
>>>
>>> I have planned with the below set up :-
>>>
>>> *2 Hard disks configured in RAID 1 for installing OS
>>> *
>>> *4 Hard disks configured in RAID 10  for data drive.*
>>>
>>> Please suggest and recommend if the above approach is correct and let me
>>> know if i am missing anything which is crucial to set up a production
>>> server. This server will host MySQL DB server.
>>
>> Is there any particular reason why you want to create two RAIDs?
>> Creating one 6 Disk RAID-10 would give you better random IOPS which is
>> useful for a DB System. You can still create two independent virtual
>> disks in that case or use independent partitions/LVM volumes to separate
>> OS from Data.
>>
>
> Hi Dennis
>
> Thanks for the reply and not sure i understand *"You can still create two
> independent virtual disks in that case"* Please explain.

Hi Kaushal,
I'm not that familiar with the Dell RAID tools but I know the PERC 
controllers they use are just rebranded LSI controllers.
On an LSI controller you can go into the WebBIOS and define your drive 
configuration (i.e. create a RAID-10 using drivegroups and spans) and 
then define virtual disks on top of that. For example you can use 6*1TB 
disks to form a 3TB RAID-10 and then define a 20G virtual disk for the 
OS and use the remaining space for a data virtual disk.

Back in the days there was no distinction between a RAID and a virtual 
disk. The RAID *was* the virtual disk.
On modern controllers the definition of the RAID topology and the 
definition of virtual disks on top of that are usually two independent 
steps.

Regards,
   Dennis