----- Original Message ----- 
From: "Al Boldi" <[EMAIL PROTECTED]>
To: "JaniD++" <[EMAIL PROTECTED]>
Cc: <[email protected]>
Sent: Monday, December 19, 2005 12:16 PM
Subject: Re: RAID0 performance question


> JaniD++ wrote:
> > For me, the performance bottleneck is cleanly about RAID0 layer used
> > exactly as "concentrator" to join the 4x2TB to 1x8TB.
>
> Did you try running RAID0 over nbd directly and found it to be faster?

Now i trying the NBD + RAID0 without the middle layer raid1.
I wondering, the speed is much more better!

If i use dd in the raid0 and the raid1 layer is active, the traffic is
350-400Mbit/s
If i use dd in the raid0 and the raid1 layer is inactive, the traffic is
512-620Mbit/s!
If i use parallel dd on all NBD devices, the traffic is 650-720Mbit/s.

(on my system's current minimal load)

I found it very interesting!
The kernel never reports timing information about raids in
/sys/block/mdX/stat files!

I cannot understand...

Cheers,
Janos

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