On Sun, Jan 22, 2006 at 05:43:24PM +0000, Alasdair G Kergon wrote:
> On Wed, Jan 18, 2006 at 04:41:57PM -0500, David Wysochanski wrote:
> > I'm wondering where the value of 1000 came from, and
>
> Thin air.
>
> > whether that's really a good default.
>
> Unlikely.
>
> That's why we made it configurable - to make it easy to try out
> different values and use whatever you find best.
>
I'm less and less confident we can find good figures, even for a specific workload.
Here is another round of numbers.
Is there still a plan for pluging the elevator in the devmapper device ?
This could help us produce predictable figures (the ones admins like).
Regards,
cvaroqui
Hardware :
- 2x2Gb/s Qlogic HBA
- 1x100GB Vraid1 in a 2C2D EVA3000 StorageWorks array
Test :
- 1 streaming read at a time
- Variations of rr_min_io and dd blocksize
Results :
min_io dd block size (kB)
4 8 16 32 64 128 256 512 1024
8 111 53 51 47 32 59 50 41 61
16 28 79 46 55 112 52 83 68 61
32 41 33 46 31 116 36 75 106 37
64 48 36 67 36 81 54 71 53 47
128 46 46 57 54 66 54 66 59 44
256 56 50 63 63 69 53 57 55 63
512 56 49 55 58 66 60 88 56 57
1024 62 54 70 62 91 82 89 61 61
Script used :
#!/bin/bash
MULTIPATH=/root/foo/multipath/multipath
DEV=/dev/mapper/mpath1
DD="sg_dd sync=1 time=1 dio=1"
SIZE="1024*1024"
MINIO="8 16 32 64 128 256 512 1024"
BS="4 8 16 32 64 128 256 512 1024"
#
# @1 : desired min_io
#
function set_minio
{
sed s/XX/$1/ /root/multipath.conf > /etc/multipath.conf
$MULTIPATH $MULTIPATH_OPT >/dev/nul
}
# header
echo "0 $BS"
for minio in $(echo $MINIO)
do
set_minio $minio
echo -n "$minio "
for bs in $(echo $BS)
do
count=$(($SIZE/$bs))
echo -n "$($DD if=$DEV of=/dev/null bs=${bs}k count=${count} 2>&1|head -1|awk '{print $8}') "
done
echo
done
--
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
