Re: Why RAID1 half-speed?

[Ingo Molnar]

On Mon, 30 Aug 1999, Mike Black wrote:

> I just set up a mirror this weekend on an IDE RAID1 - two 5G disks on the
> same IDE bus (primary and master).

> /dev/hda:
>  Timing buffer-cache reads:   64 MB in  0.95 seconds =67.37 MB/sec
>  Timing buffered disk reads:  32 MB in  3.28 seconds = 9.76 MB/sec
> 
> /dev/md0:
>  Timing buffer-cache reads:   64 MB in  0.85 seconds =75.29 MB/sec
>  Timing buffered disk reads:  32 MB in  6.10 seconds = 5.25 MB/sec

could you also show the RAID0 results? That one should quite accurately
show the effect of master/slave interaction. Some IDE chipsets do not
handle it high-performance at all. 

-- mingo