FFSv1 performance on large filesystems

[email protected] (Matthias Scheler) Thu, 3 Mar 2005 13:05:51 +0000 (UTC)

Newsgroups	gmane.os.netbsd.devel.performance
Organization	Z'Ha'Dum - home of the shadows
Message-ID	<[email protected]>

	Hello,

while searching for the reason for the "bad" NFS performance in my home
network I got interesting filesystem performance numbers

Filesystem Size		Device	Write Performance(*)
1.9G			raid0	34MB/Sec
101G			raid0	22MB/Sec <--
9.7G			raid1	34MB/Sec
26G			raid1	33MB/Sec

It looks like FFSv1 has a performance problem with large partitions. Any
ideas why that would happen? I wonder if it distributes the data too
much and therefore renders the 8MB cache of my IDE disks useless.

	Kind regards

(*) Measured with "dd if=/dev/zero of=test.img bs=1024k count=256"

-- 
Matthias Scheler                                  http://scheler.de/~matthias/