On Wed, Jul 06, 2005 at 02:09:27PM +0100, David Brownlee wrote:
> 	It might be interesting to compare two simultaneous dds to wd0

I don't see the point in that because the results is obvious:

Raw read performance ("dd if=/dev/r<x> of=/dev/null bs=1024k count=4096"):
wd0+wd0			25064001 bytes/sec + 25064147 bytes/sec

> 	and then to raid0, to see any alternative benefit.


> 	Its great that you are posting these. Other interesting values
> 	might if the frag/block size was changed to 2k/16k and 4k/32k.

Here are the values from the disklabel for a physical partition:

# /dev/rwd1d:
type: ESDI
disk: WDC WD1600JD-00G
label: fictitious
flags:
bytes/sector: 512
sectors/track: 63
tracks/cylinder: 15
sectors/cylinder: 945
cylinders: 330774
total sectors: 312581808
rpm: 7200
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # microseconds
track-to-track seek: 0  # microseconds
drivedata: 0 
[...]
 p: 169861860 142719570     4.2BSD   1024  8192 46672  # (Cyl. 151026 - 330773)

This is the RAIDframe label after "newfs":

# /dev/rraid0d:
type: RAID
disk: raid
label: fictitious
flags:
bytes/sector: 512
sectors/track: 128
tracks/cylinder: 8
sectors/cylinder: 1024
cylinders: 165880
total sectors: 169861760
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # microseconds
track-to-track seek: 0  # microseconds
drivedata: 0 

4 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 c: 165880/5/0     0/0/0     unused      0     0        # (Cyl.      0 - 165880*)
 d: 165880/5/0     0/0/0     4.2BSD   2048 16384 28832  # (Cyl.      0 - 165880*)

So the blocksize is different (thanks to Havard for asking me to check this).
I've now forced it to 8192 bytes which resulted in this disklabel:

# /dev/rraid0d:
type: RAID
disk: raid
label: fictitious
flags:
bytes/sector: 512
sectors/track: 128
tracks/cylinder: 8
sectors/cylinder: 1024
cylinders: 165880
total sectors: 169861760
rpm: 7200
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0           # microseconds
track-to-track seek: 0  # microseconds
drivedata: 0 

4 partitions:
#        size    offset     fstype [fsize bsize cpg/sgs]
 c: 165880/5/0     0/0/0     unused      0     0        # (Cyl.      0 - 165880*)
 d: 165880/5/0     0/0/0     4.2BSD   1024  8192 46672  # (Cyl.      0 - 165880*)

The filesystem performance got however not improved much. Extracting the
source files now took 7:02.43 [min:sec].

	Kind regards

-- 
Matthias Scheler                                  http://scheler.de/~matthias/