[KLUG Hardware] "new" RAID level

[Mike Williams]

I give this about 3 responses before it gets forced into advocacy, but 
here goes my rant anyway.  A couple of new high-end motherboards are 
using a Highpoint RAID chip that claims to offer something called RAID 
1.5.  Now they don't pretend that this is a combination of  RAID 1 and 
5, but a sort of  "RAID 1 and a half".  What it actually is, however, is 
just RAID 1 done right.  Most one-chip IDE RAID cards (as somebody on 
list here has explained to me) do all of their RAID calculations in 
software.  What's worse is that if you use RAID 1 (mirroring) with most 
of them, the drives are not equal in the eyes of the controller.  It 
only ever reads from one drive, so there's no performance advantage over 
a single drive on reads, and a disadvantage on rights.  All this RAID 
1.5 does is alternate read requests between the two drives, which any 
real RAID 1 implementation should be doing anyway.  There's no reason 
not to when the drive contents are identical and it seems to me to be a 
trivial amount of extra code. 

The part that bothers me is that in the IDE world, broken RAID 1 has 
become such a standard that they have to invent another name for it when 
somebody finally does it right.