On Sun, 18 Mar 2018 16:05:05 +0100 Martin Husemann <mar...@duskware.de> 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.