mfs and buildworlds on the SunFire x4600

[Mars G. Miro]

On 5/8/07, Oliver Fromme <olli at lurza.secnetix.de> wrote:
> 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
> disappointed.
>
>  > 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
> the cache.
>
>  > > > 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.)
>

I would if I could, but 200704 CURRENT doesnt run on the x4600,
exhibiting similar issues as w/ the x4100 that i posted last month in
-current.


> Best regards
>    Oliver
>
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>


cheers
mars