Re: NetBSD disk performance on VirtualBox

[Sad Clouds <cryintothebluesky%gmail.com@localhost>]

On Sun, 18 Mar 2018 16:05:05 +0100
Martin Husemann <martin%duskware.de@localhost> wrote:

> On Sun, Mar 18, 2018 at 02:08:53PM +0000, Sad Clouds wrote:
> > Hello, I tend to use dd to estimate I/O throughput
> > 
> > dd if=/dev/zero of=out bs=1m count=1000
> 
> Ok, so it is about in-filesystem writes.
> 
> Assuming you use ffs, you could test with the "log" or the "async"
> and no special mount option. All three should get different speeds,
> and we'll see if this is a file system (maybe default options) issue
> or something driver specific.
> 
> Martin

Hello, using 'log' or both 'async, log' does not improve things much,
i.e. it's around 30-50 MBytes/sec:

localhost# mount | grep wd0a
/dev/wd0a on / type ffs (asynchronous, log, local)

localhost# dd if=/dev/zero of=out bs=1m count=1000
1000+0 records in
1000+0 records out
1048576000 bytes transferred in 21.330 secs (49159681 bytes/sec)


Writing to raw device is much faster, around 250 MBytes/sec:

localhost# dd if=/dev/zero of=/dev/rwd1d bs=1m count=1000
1000+0 records in
1000+0 records out
1048576000 bytes transferred in 4.109 secs (255190070 bytes/sec)


Looks like writing to FFS peaks at around 50 MBytes/sec.