Re: NetBSD disk performance on VirtualBox

[D'Arcy Cain <darcy%NetBSD.org@localhost>]

On 03/18/2018 08:41 AM, Sad Clouds wrote:
> Hello, are there known I/O performance issues with NetBSD on VirtualBox?
> I've setup two similar VMs, one Linux, another one NetBSD, both use
> SATA virtual controller with one disk.
> 
> Writing 1GB file sequentially:
> - Linux gives 425MB/sec,

So about 3400 Mbps.  That's faster SATA I and II and not that much less
than SATA III and that's just the drive interface.  Actual writing to
the drive is closer to 150 Mbps.  Maybe more in newer drives.

> - NetBSD gives 27MB/sec.

That's around 200 Mbps.  That seems closer to the actual drive speed.

It looks to me like Linux is reporting the write completed as soon as it
is passed to the kernel while NetBSD waits until it has at least been
passed to the drive interface.  I hope that system has good battery backup.

-- 
D'Arcy J.M. Cain <darcy%NetBSD.org@localhost>
http://www.NetBSD.org/ IM:darcy%Vex.Net@localhost