Re: About seting up Raid5 on a four disk box.

[Bill Davidsen <davidsen@tmr.com>]

Antonio Perez wrote:
> Majed B. wrote:
>
>   
>> Your applications can request as much files as they want regardless of
>> their location, but the mechanical heads move together, so they can be
>> at a single location at a point of time reading a single stream of a
>> file (or multiple files if they were next to each other on the
>> physical platter).
>>     
>
> Yes that's completely correct, and it's the job of the "elevator" (*) on the 
> "md" code to decide which sector, and in what order, such sectors will be 
> serviced. If the "elevator" is aware of the underlying hardware, it will do 
> the right thing if there are several md or just one.
>
>   
The elevator is part of disk access, not md. It schedules head motion 
for all users of the drive.

> *(I am not an expert on this, is just what I got from Robin)
>
>   


-- 
Bill Davidsen <davidsen@tmr.com>
  Unintended results are the well-earned reward for incompetence.