[Samba] aio settings for samba 4.3

[Jeremy Allison]

On Tue, Jul 19, 2016 at 12:49:09PM -0500, Russell R Poyner wrote:
> I'm tuning a samba 4.3 install on freebsd and I'm confused about aio
> settings.
> 
> I've loaded the freebsd aio kernel module and tried various values
> or aio read size and aio write size, but it seems to make no
> difference in the speed.
> 
> Using MS diskspd against a samba share from a fast zfs pool I get
> something like 25MB/s tops. That's well below the capacity of my Gb
> network and my disk system. FWIW iperf shows >900Mbits/sec in both
> directions on the link.
> 
> # smbd -b|grep aio
>    vfs_aio_fork_init
>    vfs_aio_posix_init
>    vfs_aio_pthread_init

You don't need these, modern Samba includes a pthread pool
implementation that will parallelize SMB io requests.

Ensure the clients are using SMB2 and SMB2 leases are
enabled. You should be able to get close to wirespeed.