RAID 10-LUN Question

Derek Ragona derek at
Thu Feb 15 13:59:41 UTC 2007

To determine the optimal stripe size you need to analyze whether you will 
read and write large data chunks or smaller data chunks.  Then opt for 
either a larger or smaller stripe size.  Remember though that the larger a 
stripe the more potential for wasted disk space.

In general you can either manage RAID in the hardware, or in the hardware 
along with some OS compatible software.  Running RAID 10 with hot spares 
makes the OS management piece not terribly necessary except to see the 
array status and any RAID failures.  These will also show up on the console 
when the system is booted.  If this server will be remotely managed you 
will want to use software from within the OS to manage the RAID.


At 10:29 PM 2/14/2007, Dak Ghatikachalam wrote:

>At 02:54 PM 2/14/2007, Dak Ghatikachalam wrote:
>>Hi Freebsd
>>We have DELL/EMC CX-300 storage array hardware , Navisphere. , which consist
>>of  15 Disks 320GB, I am planning to use this for Oracle( Linux) + SQL
>>server(M$) purpose.
>>We need to get that redundancy using RAID 10 and  striple for the best
>>My thoughts are  take most even number of possible disks( leaving private
>>system partition area) and create the raid groups and kick a separate LUNS
>>for MSSQL purpose.
>>With this hardware config, Do you have any suggestion on getting the best
>>performance and redundancy in place
>On 2/14/07, Derek Ragona 
><<mailto:derek at>derek at > wrote:
>>RAID 10 uses even numbered drive sets, usually in 4's, so 4 drives, 8 
>>drives, 12 drives, etc.  Depending on how 24/7 self-managed you want the 
>>array, you should plan for at least 2 hot spare drives for fail over.
>>So in your setup you could have one logical array made up of 12 drives, 
>>with 2 spares, and one left for the OS.  One consideration in striping is 
>>the stripe size.  Stripe size effects performance but also storage 
>>efficiency.  So you want to balance those factors in choosing a stripe size.
>How to determine the stripe size  Dell recommends the OS striped across 5 
>disks and calls itself system private paritition
>How to determine the optimal stripe size, will I be able to ditch  the 
>current navisphere the Storage Array OS( which is now windows based I 
>t  and stick Freebsd  in its place. We have got nice GEOM ability now.
>>One last issue, is make sure you have enough cache on the RAID controller.
>>         -Derek
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