bzr-svn/bzr-git, Linux and NFS

[Russel Winder]

On Tue, 2009-09-15 at 08:01 +1000, Martin Pool wrote:
> 2009/9/14 Russel Winder <russel.winder at concertant.com>:
> > The background to this is that bzr-svn and bzr-git both make use of TDB.
> > TDB makes use of mmap and it appears to be a known fact that Linux has
> > extremely serious performance problems with mmap over NFS mounted
> > filestores.
> 
> How about passing TDB_NOMMAP when opening it then?  (That might
> require tweaking the Python bindings.)

I believe Jelmer doesn't want to get involved in what I think he sees as
a dark corner case -- but I may be interpreting his emails incorrectly.
I guess the question is whether detection of the mount being an NFS one
instead of a local disc is easy, or even possible.  Also of course
whether not using mmap interferes with the ability to have multiple
connections to the same repository (which is why TDB is used in
preference to SQLite). 
-- 
Russel.
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Dr Russel Winder      Partner
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