8.1 amd64 lockup (maybe zfs or disk related)

[Jean-Yves Avenard]

On 7 February 2011 20:03, Jeremy Chadwick <freebsd at jdc.parodius.com> wrote:

> They're discussed practically on a monthly basis on the mailing lists
> (either freebsd-fs or freebsd-stable).  Keeping track of them is almost
> impossible at this point, which is also probably why the Wiki is
> outdated.

I like Sun's take on the matter:

http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Tuning_is_Evil
"Tuning is often evil and should rarely be done.

First, consider that the default values are set by the people who know
the most about the effects of the tuning on the software that they
supply. If a better value exists, it should be the default. While
alternative values might help a given workload, it could quite
possibly degrade some other aspects of performance. Occasionally,
catastrophically so.

"

Which I thing summarise perfectly ZFS "tuning".

If you want to know 20 differents opinions on how zfs needs to be
tuned; talk to 20 different people.
Everyone has their own ideas on how it should be done ; believe a
particular setting made things better.

I tried them all I could read here, none of them make much significant
difference, and and when they do, usually it's just for the worse.