Dean wrote:
> I did a write IO test in IBM P690 and HP SUPERDOME.
> When I tested the local disks in P690,use this:
> ----------------------------------------------------
> time dd if=/dev/zero of=/tmp/test.dat bs=1024 count=300000
> 300000+0 records in
> 300000+0 records out
> real 0m42.01s
> user 0m0.85s
> sys 0m6.18s
> The Speed should be 7MB/s almost,and the P690 is running none except
> this.
>
> When I tested the local disks in the SUPERDOME,
> ---------------------------------------------
> time dd if=/dev/zero of=/tmp/test.dat bs=1024 count=300000
> 300000+0 records in
> 300000+0 records out
>
> real 2.9
> user 0.2
> sys 2.5
> The Speed should be 100MB/s almost!!!!
> =======================================
> I used the same method to test the Storage of HDS 9980,which is
> connected to the P690 and SUPERDOME.
> -----------------------------
> the result of P690 is 56MB/s almost,and result of SUPERDOME is 90MB/s
> almost !!!
>
> I'll cry for explaining this to the customer.
> Anyone can help me to explain this?


On a 7043-150

time dd if=/dev/zero of=/dev/null count=300000
300000+0 records in.
300000+0 records out.

real 0m12.72s
user 0m4.58s
sys 0m8.14s

Don't assume that /dev/zero and /dev/null times are negligable. They
aren't necessarily written efficiently or intended for use in benchmarks.

-- Jason