Re: Benchmarks: Linux Kernel RAID vs a Hardware RAID setup

[Ben Martin <monkeyiq@users.sourceforge.net>]

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On Tue, 2008-07-15 at 10:42 -0400, Justin Piszcz wrote:
> What were the commands used when creating the XFS filesystem 
> (sunit,swidth)?
> 
> Justin.

I noticed that on the hardware card I had to use nobarrier to get decent
file metadata performance (create,del etc). I have noticed also recently
on an 32gb Mtron SSD that with barriers enabled with XFS on the SSD
metadata performance was an order of magnitude slower.

The below is a snippit from the hardware RAID testing config. The XFS
creation and mounting args are identical for software RAID.

#!/bin/bash

RAIDLEVEL=6
CHUNK_SZ_KB=256
PARITY_DRIVE_COUNT=2
NON_PARITY_DRIVE_COUNT=4
DEVICE=/dev/disk/by-id/scsi-SAdaptec_1024ktmpraid6
...
run_bonnie() {
    fsdev=$1
    mountopts=$2
    N=256

    mount -o "$mountopts" $DEVICE /mnt/tmpraid
    chown ben /mnt/tmpraid
    sync 
    sleep 1
    sudo -u ben /usr/sbin/bonnie++ -q -m $fsdev -n $N -d \
         /mnt/tmpraid >>/T/adaptec-raid
${RAIDLEVEL}-${CHUNK_SZ_KB}kb-chunks-bonnie.csv
    umount /mnt/tmpraid
}

...

fsdev=hardxfsdefaultnb
mkfs.xfs -f -l lazy-count=1 \
        $DEVICE
run_bonnie $fsdev "nobarrier"

fsdev=hardxfsalign
mkfs.xfs -f -s size=4096 \
	-d sunit=$(($CHUNK_SZ_KB*2)),swidth=$(($CHUNK_SZ_KB*2*
$NON_PARITY_DRIVE_COUNT)) \
	-l lazy-count=1 \
        $DEVICE
run_bonnie $fsdev "nobarrier"

fsdev=hardxfsdlalign
mkfs.xfs -f -s size=4096 \
	-d sunit=$(($CHUNK_SZ_KB*2)),swidth=$(($CHUNK_SZ_KB*2*
$NON_PARITY_DRIVE_COUNT)) \
        -l lazy-count=1,sunit=$((CHUNK_SZ_KB*2)),size=128m \
        $DEVICE
run_bonnie $fsdev "nobarrier"

# run iozone on it.
fsdev=hardxfsalign
mkfs.xfs -f -s size=4096 \
	-d sunit=$(($CHUNK_SZ_KB*2)),swidth=$(($CHUNK_SZ_KB*2*
$NON_PARITY_DRIVE_COUNT)) \
	-l lazy-count=1 \
        $DEVICE
mount -o "nobarrier" $DEVICE /mnt/tmpraid
chown ben /mnt/tmpraid
sync 
sleep 1
sudo -u ben iozone -a -g 4G -f /mnt/tmpraid/iozone_file  \
   >/T/adaptec-raid${RAIDLEVEL}-${CHUNK_SZ_KB}kb-chunks-iozone.txt
umount /mnt/tmpraid


> 
> On Wed, 16 Jul 2008, Ben Martin wrote:
> 
> > Hi,
> >  Apologies if posting this here is inappropriate but a recent article
> > of mine compares the Linux Kernel RAID code to an $800 hardware RAID
> > card and might be of interest to list members:
> >
> > http://www.linux.com/feature/140734
> >
> >

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