Re: subversion on NFS

Hi,

We ran into problems with Subversion 1.4.5 using the worker MPM because
the apr-util library which controls the DAV activities database uses DBM
files to track changes.

DBM files require POSIX locks to be able to be held on files - since
threads aren't real processes they don't obey POSIX locking properly and
so corruption to your repository can occur - particular when large commits
are taking place.

Lieven Govaerts pointed out to me on the "Shared storage for subversion
repository" thread that "Subversion 1.5 has its own file-based mechanism
for maintaining the DAV activity mappings, so the above is no longer
true." So it could well be that the worker MPM may now be feasible.

We're consuming 1TB of storage across 1056 repositories which are
receiving approx 3,500 commits per day. These are being hosted by a single
headed Apache host which has 2 x dual-core Xeon 2.66GHz and 16Gb of RAM.
The NFS data is held on a FAS3050 NetApp filer which is replicated to a DR
site via NetApp SnapMirror software. There is identical hardware in both
production and DR with identical software and configuration.

Dg.

--
David Grierson
JPMorgan - IB Architecture - Source Code Management Consultant
GDP 228-5574 / DDI +44 141 228 5574 / Email david.x.grierson_at_jpmorgan.com
Alhambra House 6th floor, 45 Waterloo Street, Glasgow G2 6HS
 
Murli Varadachari <mvaradachari_at_facebook.com> 
23/09/2008 15:38
To
Steve Whitson <steven.whitson_at_gmail.com>, <users_at_subversion.tigris.org>
cc
Internal Use <mvaradachari_at_facebook.com>
Subject
Re: subversion on NFS
I have just set up a shared subversion repository [ on a NFS partition ] 
and am in the process of testing simultaneous read-writes from a number of 
hosts.  SO far the tests seem ok. The current setup uses svn+ssh 
protocols.
Down the road I intend to use both http(s) and svn protocols.
I am curious why you ran into corruption problems using “worker mpm” -- is 
that still a problem with svn 1.5.  [ on a fedora core linux ]
Also you mentioned that you are using about 1TB of repository storage — is 
that a single repository.??
Cheers
murli
On 9/23/08 7:19 AM, "Steve Whitson" <steven.whitson_at_gmail.com> wrote:
Thanks David,  I appreciate your feedback!
david.x.grierson_at_jpmorgan.com wrote:
> Hi,
>
> We successfully run our services from NFS stored repositories using the
> Apache prefork MPM serving over 1TB of repository storage transferring 
an
> average of over 60GB of traffic per day (1920.60Gb of data transferred 
for
> August).
>
> When I upgraded to 1.4.5 early this year I ran into repository 
corruption
> problems - these turned out to be because I had switched over to using 
the
> worker MPM.
>
> Regards,
>
> Dg.
> --
> David Grierson
> JPMorgan - IB Architecture - Source Code Management Consultant
> GDP 228-5574 / DDI +44 141 228 5574 / Email 
david.x.grierson_at_jpmorgan.com
> Alhambra House 6th floor, 45 Waterloo Street, Glasgow G2 6HS
> 
>
>
>
> Steve Whitson <steven.whitson_at_gmail.com>
> 22/09/2008 20:26
>
> To
> "users_at_subversion.tigris.org" <users_at_subversion.tigris.org>
> cc
>
> Subject
> subversion on NFS
>
>
>
>
>
>
> When serving subversion (1.5.2 fsfs) through apache (2.2.9)... (this is
> on a Solaris 10 system with nfs from netapp).
>
> I see where subversion should not be used with the apache worker MPM
> module.  Is using the prefork MPM module ok?
>
> Another question I have, can I allow svnserve access to my set of
> repositories (read/write) while at the same time serving them up through
> apache (something I'm toying with) or is doing this going to eventually
> cause corruption?
>
> I've read the FAQ on NFS, and several past threads:
>     http://subversion.tigris.org/faq.html#nfs
>     http://svn.haxx.se/users/archive-2008-05/0048.shtml
>     http://svn.haxx.se/dev/archive-2007-04/0288.shtml
>
> Thanks much,
>     -Steve
>
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is virus free and no responsibility is accepted by JPMorgan Chase &
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or damage arising in any way from its use. If you received this
transmission in error, please immediately contact the sender and
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copy format. Thank you.
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