raid3 is slow

[R. B. Riddick]

--- Szabó Péter <matyee at mail.alba.hu> wrote:
> A SATA cable was wrong, and the 5th disk of the raid was not connected. Now 
> i fix it.
>
> Geom name: nmivol
> State: COMPLETE
>
OK... :-)

> # apply "dd if=/dev/ad%1 of=/dev/null bs=1m count=250 &" 0 1 2 3 4
> 250+0 records out
> 262144000 bytes transferred in 4.324466 secs (60618814 bytes/sec)
> 250+0 records in
> 250+0 records out
> 262144000 bytes transferred in 6.289833 secs (41677418 bytes/sec)
> 250+0 records in
> 250+0 records out
> 262144000 bytes transferred in 6.262564 secs (41858894 bytes/sec)
> 250+0 records in
> 250+0 records out
> 262144000 bytes transferred in 7.871292 secs (33303808 bytes/sec)
> 250+0 records in
> 250+0 records out
> 262144000 bytes transferred in 7.857484 secs (33362333 bytes/sec)
>
Looks good...

> I forgot to tell, one label of the raid is a gbde encoded partition. If i do 
> a read test from the raid, the load seems normal?!?! I don't know how high 
> is normal.
>
And why is that?
I mean: It doesnt encrypt the data really, because graid3 can still read with a
missing disk (consumer)...
 
> # dd if=/dev/raid3/nmivol of=/dev/null bs=1m count=30000
> 30000+0 records in
> 30000+0 records out
> 31457280000 bytes transferred in 336.545001 secs (93471244 bytes/sec)
>
Doesnt look much faster than before (86MB/sec or so?)...


What happens, when u do not use a gbde device as a consumer?

What happens when u try to read from a file system on top of the graid3 device?

-Arne


 
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