Re: Heads up

On Fri, Apr 22, 2016 at 12:33 PM, Ivan Klymenko <fidaj_at_ukr.net> wrote:

> On Thu, 14 Apr 2016 16:42:33 -0600
> Warner Losh <imp_at_bsdimp.com> wrote:
>
> > The CAM I/O scheduler has been committed to current. This work is
> > described in
> > https://people.freebsd.org/~imp/bsdcan2015/iosched-v3.pdf though the
> > default scheduler doesn't change the default (old) behavior.
> >
> > One possible issue, however, is that it also enables NCQ Trims on ada
> > SSDs. There are a few rogue drives that claim support for this
> > feature, but actually implement data corrupt instead of queued trims.
> > The list of known rogues is believed to be complete, but some caution
> > is in order.
> >
> > Warner
>
> Hi.
>
> I have the small issue.
> I have one hard drive with zfs.
> If i beginning cloning the hard drive in VirtualBox machine - this
> process is very slow 1,5-2 hours.
> Without CAM_NETFLIX_IOSCHED options - this process two or three times
> faster.
> With this is possible to do something?
>

I don't know. I've not investigated this in enough detail to know. One
thing you might change is the read bias from 300 to 1, which may be
more appropriate for your workload.

Warner