Re: RAID-1 performance under 2.4 and 2.6

[Emmanuel Florac <eflorac@intellique.com>]

Le Wed, 26 Mar 2008 12:15:57 +0100
"Bart Van Assche" <bart.vanassche@gmail.com> écrivait:

> You are welcome to post the numbers you obtained with dd for direct
> I/O on a RAID-1 setup for 2.4 versus 2.6 kernel.

Here we go (tested on a slightly slower hardware : Athlon64 3000+,
nVidia chipset) . Actually, direct IO result is identical. However, the
significant number for the end user in this case is the NFS thruput.

2.4 kernel (2.4.32), async write
--------------------------------
root@0[root]# ./dd if=/dev/zero of=/mnt/raid/testdd01 bs=1M count=1024 
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 13.407 seconds, 80.1 MB/s

2.4 kernel (2.4.32), async write thru NFS mount
--------------------------------
emmanuel[/mnt/temp]$ dd if=/dev/zero of=./testdd01 bs=1M count=1024 
1024+0 enregistrements lus
1024+0 enregistrements écrits
1073741824 bytes (1,1 GB) copied, 15,5176 s, 69,2 MB/s

2.4 kernel (2.4.32), async read
--------------------------------
root@0[root]# ./dd if=/mnt/raid/testdd01 of=/dev/null bs=1M
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 15.752 seconds, 68.2 MB/s

2.4 kernel (2.4.32), sync write
--------------------------------
root@0[root]# ./dd if=/dev/zero of=/mnt/raid/testdd01 bs=1M count=1024 \
oflag=direct,dsync 
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 21.7874 seconds, 49.3 MB/s

2.6 kernel (2.6.22.18), async write
--------------------------------
root@0[root]# ./dd if=/dev/zero of=/mnt/raid/testdd02 bs=1M
count=1024 1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 17.1347 seconds, 62.7 MB/s

2.6 kernel (2.6.22.18), async write thru NFS mount
--------------------------------
emmanuel[/mnt/temp]$ dd if=/dev/zero of=./testdd02 bs=1M count=1024
1024+0 enregistrements lus
1024+0 enregistrements écrits
1073741824 bytes (1,1 GB) copied, 21,3618 s, 50,3 MB/s

2.6 kernel (2.6.22.18), async read
--------------------------------
root@0[root]# ./dd if=/mnt/raid/testdd02 of=/dev/null bs=1M
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 15.7599 seconds, 68.1 MB/s

2.6 kernel (2.6.22.18), sync write
--------------------------------
root@0[root]# ./dd if=/dev/zero of=/mnt/raid/testdd02 bs=1M count=1024 \
oflag=direct,dsync 
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 21.7011 seconds, 49.5 MB/s

-- 
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Emmanuel Florac     |   Intellique
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