[Gluster-devel] webservers vs. glusterfs vs. namespace

Sun Jan 20 13:39:38 UTC 2008

find /glustefs/mntpnt/* -type f -print0 | xargs -0 -l100 -n100 -P N md5sum

how the sistem performs as N increases? 
Is this test as slow as apache2 access?

from: http://httpd.apache.org/docs/2.0/misc/perf-tuning.html
you can read that 

Memory-mapping

In situations where Apache 2.x needs to look at the contents of a file being delivered--for example, when doing server-side-include 
processing--it normally memory-maps the file if the OS supports some form of mmap(2). 

On some platforms, this memory-mapping improves performance. 
However, there are cases where memory-mapping can hurt the performance or even the stability of the httpd:

On some operating systems, mmap does not scale as well as read(2) when the number of CPUs increases. On multiprocessor Solaris 
servers, for example, Apache 2.x sometimes delivers server-parsed files faster when mmap is disabled.
If you memory-map a file located on an NFS-mounted filesystem and a process on another NFS client machine deletes or truncates the 
file, your process may get a bus error the next time it tries to access the mapped file content.

For installations where either of these factors applies, you should use EnableMMAP off to disable the memory-mapping of delivered files. 
(Note: This directive can be overridden on a per-directory basis.)

Can you rey EnableMMAP off?

¿Is mmaping the problem?

El Domingo, 20 de Enero de 2008 Sascha Ottolski escribió:
> Am Sonntag 20 Januar 2008 01:38:28 schrieb Anand Avati:
> > Sascha,
> >  Please run by removing AFR (make AFR's first subvolume a direct
> > subvolume of unify). AFR can potentially flush io-cache pages while
> > doing read scheduling across subvolumes (by returning inconsistent
> > mtimes with the read buffer). we are working on fixing this.
> >
> > avati
> 
> I will try this, but isn't it still strange that the caching _does_ work 
> with the exact same config for apache-1.3? I would hope that this 
> different behaviour could be related to the unexpected slowness of the 
> other werbservers (which also is there with caching disabled!).
> 
> Thanks, Sascha
> 
> 
> >
> > 2008/1/20, Sascha Ottolski <ottolski at web.de>:
> > > Am Sonntag 20 Januar 2008 01:14:06 schrieb Anand Avati:
> > > > can you please share your spec files with glusterfs.pastebin.com
> > > > ?
> > >
> > > my pleasure: http://glusterfs.pastebin.com/m8820300
> > >
> > >
> > > Thanks for your time,
> > >
> > > Sascha
> > >
> > > > thanks,
> > > > avati
> > > >
> > > > 2008/1/20, Sascha Ottolski <ottolski at web.de>:
> > > > > Am Samstag 19 Januar 2008 11:03:43 schrieb Sascha Ottolski:
> > > > > > Am Freitag 18 Januar 2008 17:49:15 schrieb Anand Avati:
> > > > > > > Sascha,
> > > > > > >  the reason why 1.3.0pre4 might be faster would not be
> > > > > > > because of the missing namespace, but most likely because
> > > > > > > of missing self-heal. can you try with 'option self-heal
> > > > > > > off' in the unify section?
> > > > > >
> > > > > > may ask again, any idea why the old apache-1.3 performs way
> > > > > > better on either gluster version than the others? or any idea
> > > > > > which knobs to tweak to get more out of the others?
> > > > >
> > > > > now, another astonishing observation: if I enable the io-cache,
> > > > > it has a good effect for apache1 (almost doubles the
> > > > > requests/second), but almost none for apache2, nginx and
> > > > > lighttpd.
> > > > >
> > > > > could this help to understand more about the performance
> > > > > differences?
> > > > >
> > > > >
> > > > > Thanks, Sascha
> > > > >
> > > > > > usally, for static files from a local fileseystem, one would
> > > > > > expect that nginx and lighttpd would outperform the apaches
> > > > > > remarcably...may be my observations have a common cause with
> > > > > > those of
> > > > > > http://lists.nongnu.org/archive/html/gluster-devel/2008-01/ms
> > > > > >g001 42.h tml ?
> > > > > >
> > > > > >
> > > > > > Thanks a lot, Sascha
> > > > > >
> > > > > > > are the test results same for multiple runs too?
> > > > > > >
> > > > > > > avati
> > > > > > >
> > > > > > > 2008/1/18, Sascha Ottolski <ottolski at web.de>:
> > > > > > > > Hi Folks,
> > > > > > > >
> > > > > > > > I'm wondering if anyone might have some general advices
> > > > > > > > if I miss something important in my test setup. I'm
> > > > > > > > trying to figure out how to tweak the configs to achieve
> > > > > > > > the best performance, but get result that feel strange to
> > > > > > > > me. I will post some numbers at a later point, but up to
> > > > > > > > now what I discovered is:
> > > > > > > >
> > > > > > > > - glusterfs without a namespace (1.3.0pre4) seems to be
> > > > > > > > significant faster than with namespace (tla patch-628)
> > > > > > > >
> > > > > > > > that seems to logical, at least I would expect some
> > > > > > > > overhead for the namespace.
> > > > > > > >
> > > > > > > > what i absolutely not understand is, how different the
> > > > > > > > webservers perform. i tested with
> > > > > > > >
> > > > > > > >     siege -f /tmp/siege-urls.txt.new -c100 -i -r50 -b
> > > > > > > >
> > > > > > > > with up to 3 sessions in parellel, each firing it's
> > > > > > > > requests to a seperate webserver (on seperate machines,
> > > > > > > > of course).
> > > > > > > >
> > > > > > > > up to now my ranking by means of requests/per second is
> > > > > > > > something like
> > > > > > > >
> > > > > > > > 630 | apache
> > > > > > > > 430 | apache2 (worker)
> > > > > > > > 350 | nginx
> > > > > > > > 250 | lighttpd
> > > > > > > >
> > > > > > > > (with 1.3.0pre4 and no namespace, the best I've seen was
> > > > > > > > apache2 with about 900, apache still 750). I must admit
> > > > > > > > that up to now I did not compare it to local filesystem,
> > > > > > > > but from my past experiences with webservers I would
> > > > > > > > expect nginx and lighttpd way ahead of the apaches...
> > > > > > > >
> > > > > > > > Also, I exprimented a bit with different settings for
> > > > > > > > io-threads on the server (1, 2, 4, 8, and cache-size 64
> > > > > > > > or 128MB), but that didn't seem to make much of a
> > > > > > > > difference. Same with read-ahead (which seems logical, as
> > > > > > > > I test with relatively small images).
> > > > > > > >
> > > > > > > > So far I did not try the booster. I use fuse-2.7.0-glfs7.
> > > > > > > > I also did not try the latest tla nor fuse-2.7.2-glfs8.
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks a lot for any pointer,
> > > > > > > >
> > > > > > > > Sascha
> > > > > > > >
> > > > > > > >
> > > > > > > > _______________________________________________
> > > > > > > > Gluster-devel mailing list
> > > > > > > > Gluster-devel at nongnu.org
> > > > > > > > http://lists.nongnu.org/mailman/listinfo/gluster-devel
> > > > > >
> > > > > > _______________________________________________
> > > > > > Gluster-devel mailing list
> > > > > > Gluster-devel at nongnu.org
> > > > > > http://lists.nongnu.org/mailman/listinfo/gluster-devel
> > > > >
> > > > > _______________________________________________
> > > > > Gluster-devel mailing list
> > > > > Gluster-devel at nongnu.org
> > > > > http://lists.nongnu.org/mailman/listinfo/gluster-devel
> 
> 
> 
> 
> _______________________________________________
> Gluster-devel mailing list
> Gluster-devel at nongnu.org
> http://lists.nongnu.org/mailman/listinfo/gluster-devel
> 

-- 
------------------------------------------------
Clist UAH @gmail!!
------------------------------------------------