mfs and buildworlds on the SunFire x4600
olli at lurza.secnetix.de
Tue May 8 13:34:49 UTC 2007
Mars G. Miro wrote:
> Oliver Fromme wrote:
> > Mars G. Miro wrote:
> > > there's been a lot of threads in teh past that a buildworld on mfs
> > > increases speed --- tho it might not be the appropriate test for
> > > high-end machines (speaking of w/c I just gots a T2000).
> > It depends on what exactly you want to test, and for
> > what reason. You probably have already wasted much
> > more time with your experiments and testing than you
> > can ever save by using mfs for buildworld.
> wasted my time? dont think so.
> now we know buildworld on mfs dont really matter on high-end machines,
No, we knew that before. I could have told you. :-)
That was the first thing I tested when I first had access
to a machine with sufficient RAM, about 10 years ago.
I put /usr/src on an MFS disk, ran buildworld, and was
> so teh conclusion would be, buildworld isnt teh appropriate test if
> mfs does really speed things up, other apps/tools may be much more
> appropriate --- that or, does mfs speeding things up really work?
> remains to be seen ...
The only case for which a memory file system is really
faster is when you're handling a huge number of inodes,
for example the ports collection. And even then a real
disk isn't much slower as soon as the whole bunch is in
> > > there's prolly other appropriate apps/tools for mfs-testing ...
> > I don't think it makes much sense to benchmark mfs.
> > It is a known fact that a real tmpfs (like Solaris and
> > Linux have) would be better. I think it's even listed
> > on the FreeBSD ideas web page, but nobody is actively
> > working on it, AFAIK. On the other hand, I'm not 100%
> > convinced that it would be worth the effort either.
> it does to me, however, and perhaps other people too ;-)
Why? I wonder why you are so eager to test MFS?
> > It would be interesting to see how ZFS on a swap-backed
> > vnode device would perform on FreeBSD 7-current (with
> > and without compression).
You didn't comment on that one. Aren't you interested in
how a ZFS-based memory disk would perform, as opposed to
a UFS-based one (a.k.a. "MFS")?
(Of course, performance isn't everything. ZFS has other
features such as compression, checksums and dynamic growth
that might be very useful for a memory disk.)
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
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