OpenZFS: kldload zfs.ko freezes on i386 4GB memory

[Cy Schubert]

In message <20201030204622.GF2033 at zxy.spb.ru>, Slawa Olhovchenkov writes:
> On Thu, Oct 29, 2020 at 08:13:00PM -0700, Cy Schubert wrote:
>
> > In message <E1kWvLj-0000GY-Ic.qroxana-mail-ru at smtp29.i.mail.ru>, qroxana 
> > writes
> > :
> > > 
> > > Hi,
> > >
> > > I have an old i386 machine running r364479. After upgrading to
> > > r367045, running kldload zfs.ko freezes the whole system.
> > >
> > > I also tried to replace the 4GB memory with another 2GB one
> > > and kldload zfs.ko works without freezing the machine.
> > 
> > ZFS ARC stresses memory. I've found a number of bad RAM chips over the 
> > years using ZFS.
> > 
> > The OpenZFS upgrade significantly changed how it manages ARC. It's likely 
> > that prior to the OpenZFS upgrade your memory wasn't stressed to the point 
> > of failure. You can try to mask the problem by reducing your RAM clock rate
>  
> > or or increase one of the other latency settings in your BIOS. However, 
> > again, this only masks an already weak RAM chip.
>
> Sounds like performance drop and regression

How so. Please explain.


-- 
Cheers,
Cy Schubert <Cy.Schubert at cschubert.com>
FreeBSD UNIX:  <cy at FreeBSD.org>   Web:  https://FreeBSD.org
NTP:           <cy at nwtime.org>    Web:  https://nwtime.org

	The need of the many outweighs the greed of the few.