Re: Multiple clients accessing git over NFS

["J. Bruce Fields" <bfields@fieldses.org>]

On Sun, Nov 14, 2010 at 06:11:41PM -0500, Greg Troxel wrote:
> 
> Khawaja Shams <kshams@usc.edu> writes:
> 
> > Is it a recommended practice to share a repository over NFS, where
> > multiple clients can be pushing changes simultaneously?  In our
> > production environment, we have a Git repository setup behind
> > git-http-backend. We would like to place multiple Apache servers
> > behind a load balancer to maximize availability and performance.
> > Before we proceed, we wanted to check to see if this practice has a
> > potential to cause repository corruption. If there are other ways
> > others have solved this problem, we would be very interested in
> > learning about those as well. Thank you.
> 
> NFS locking has historically been problematic, and my impression is that
> most people avoid it.  Perhaps it's ok on Solaris, but without serious
> testing, I'd be worried.

Does git actually do file locking when people push to a bare repo?

If all it needs is for rename and/or O_EXCL to be atomic--that should be
fine over NFS.

--b.

> 
> Can you explain what you have set up, and what your performance
> situation is, and why you think adding a second or third apache over NFS
> will help?  How many users?  How many pushes/day?
> 
> One option is to have a multi-core box with tons of RAM running apache;
> I've done that for trac (8 core, 16G, RAID5) because trac/python is so
> piggy, and buying a $3K box was cheaper than making trac go faster.
> That doesn't get you into remote FS locking issues.