Serious zfs slowdown when mixed with another file system (ufs/msdosfs/etc.).

[jhell]

On 07/11/2010 23:08, Freddie Cash wrote:
> Search the archives for the -stable, -current, and -fs mailing lists
> from the past 3 months.  There are patches floating around to fix
> this.  The ZFS code that monitors memory pressure currently only
> monitors the "free" amount, and completely ignores the "inact" and
> other "not actually in use" amounts.
> 

AFAIR, any of the patches that were around were either incomplete or
inconsistent & were good attempts to solve the problem but turned out in
the end to not effect the problem in a positive or negative way. I may
be wrong as it seems the problem has a few variables that determine its
effect in different cases, usage, hardware mixture & implementation.

If there is one thing that I have been seeing more of was the perl hack
that gets every process on your system to swap-out to free RAM for use
by ZFS or whatever its intention.

perl -e '$x = "x" x 1000000;'

It might be a good thing to mention this on the ZFS tuning section of
the wiki for reference.


Regards & Good Luck,

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