From: Holger.VanKoll@SWISSCOM.COM
Date: Tue Nov 12 2002 - 16:04:50 EST
Hello,
I got a p670 connected to HDS (Hitachi; 9900) Storage with 2 FC-adapter.
No matter how much disks I access concurrently, I get 34mbyte/sec
maximum.
All 4 CPU are 0% idle when measuring, but depending on the # disks they
spend more time in kernel than in wait.
# disks accessed kernel wait disk-busy (topas) transfer
Mbyte/sec
10-20 8 90 50-70%
25
30 40 60 40-60%
33
40 55 45 60-80%
33
50 70 30 40-60%
34
60 78 22 35-50%
34
This looks like my CPU-power is the bottleneck, correct?
As I get 184 Mbyte/sec with the 4 internal disks and 60% kernel / 40%
wait that looks to me as if the fibre-channel driver (kernel-time) uses
all my cpu. Is this correct?
If someone likes to do some measurement to have numbers to compare, here
is the script I used:
#!/bin/sh
#dlmfdrv4 - 61
count=2000
bsk=256k
dev=dlmfdrv
#dev=hdisk
start=4
end=54
i=$start
until false
do
dd </dev/$dev$i >/dev/null bs=$bsk count=$count 2>/dev/null &
[ $i = $end ] && break
let i=i+1
done
I would appreciate any other "benchmark"-results, especially latest
ssa-technology and non hds (f.e. ibm) storage servers.
Regards,
Holger
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