bhyve and zfs and speed

John freebsd-lists at
Mon Sep 8 13:12:56 UTC 2014

On Wed, Sep 03, 2014 at 12:15:28AM +0200, Nikolay Denev wrote:

> I see you have 108G free memory. Is this due to a recent reboot and
> the ARC hasn't grown much yet, or you are limiting it?

not doing anything to it - it's running defaults. Two virtual machines
are running.

> As for ZFS tuning for bhyve, I'm not aware of anything specific, but
> you should consider that values you want to put for the zvols for
> primarycache and secondarycache. (In your case only primarycache as
> you don't have L2ARC).

ok, thanks.

> Leaving this to the default might be faster but might result in double
> caching: Once in the ARC on the host system, and then on the buffer
> cache of the UFS guest.

ok - will look to see how to turn off double buffering

> For MySQL and databases in general, as far as I can remember the
> general advice was to run them on zfs datasets with lower reclen, like
> 8k for example.
> Here you have zvols which default to 8k but the vtbd device reports
> 512b sectors, not sure if you try to trick it into using larger values
> here wouldn't help.
> Also different UFS block sizes for different zvol recordlens might be
> interesting test.

Thanks again for the advice


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