[CentOS] RAID configuration suggestion???

Tue Jan 11 10:33:00 UTC 2011
John Doe <jdmls at yahoo.com>

From: mcclnx mcc <mcclnx at yahoo.com.tw>

> we have several DELL R900 with PERC 6/E adapter in it.  R900 using Redhat  
>Linux.  Each R900 have two PERC 6/E adapter and at least two MD1000 connect  to 
> Configuration 1:
>           PERC  6/E -- two MD1000
>           PERC 6/E --   empty
> Configuration 2:
>           PERC 6/E  --  MD1000
>           PERC 6/E --   MD1000
> Normally first MD1000 for database and second MD1000 for nightly  backup.  My 
>co-worker told me there is NO difference on performance or  battery life on botn 
> I would like listen to your opinion  on follwoing:
> 1. which configuration have better performance?
> 2.  put two MD1000 on same PERC 6/E adapter will cause battery life  shorter?
> 3. other comment?

  Depends on the PERC card...  I guess the onboard cache will have to be 'split' 
between the 2 devices.
  Also depends on the motherboard layout maybe...
  Does each slot have dedicated 'bus speed'?  Or do all slots have to share?

  The battery has to hold long enough to write the cached data to disk...
  Since it the same amount of cache with 1 or more devices on one card, there 
should be no differences.

  Why not just use configuration 2 if you already have the 2 cards...?