Re: Subversion repository on unix mounted dir

Hi Greg,
All of our repositories are held on NFS volumes ... when we migrated our
service from 1.3.2 (with Apache using the prefork MPM) to 1.4.5 (Apache
using the worker [threaded] MPM) we started seeing significant corruptions
in repositories which were receiving large commits to them.
I couldn't figure out the cause of the issue until I found this thread in
the svn-dev list:
http://svn.haxx.se/dev/archive-2007-04/0288.shtml
I'm not sure whether this fix has been implemented ... but as soon as we
switched back from the worker MPM to prefork the corruptions stopped
occurring.
My understanding of the issue is that apr-util is used to manage the DAV
activities database which maps DAV ID's to Subversion transactions.
apr-util uses apr_dbm which uses BDB for its internal storage.
The use of BDB on remote filesystems such as NFS will essentially not
work:
http://www.db5.org/ref/env/remote.html
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
 

Greg Thomas <thomasgd_at_omc.bt.co.uk>
07/05/2008 09:27

To
users_at_subversion.tigris.org
cc

Subject
Re: Subversion repository on unix mounted dir

On Tue, 6 May 2008 13:47:20 +0100, david.x.grierson_at_jpmorgan.com
wrote:

>Except that FAQ should be updated to stipulate that you should not use
the
>worker MPM within Apache with NFS storage.
>
>The threads won't obey the locks held on files and will (eventually -
>sooner or later depending upon the volume of activity) lead to repository

>corruption.

I'm showing my ignorance here, but why would svn code in a worker MPM
thread ignore locks when the same code won't normally?

And why is this limited to NFS?

Greg

-- 
This post represents the views of the author and does
not necessarily accurately represent the views of BT.
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe_at_subversion.tigris.org
For additional commands, e-mail: users-help_at_subversion.tigris.org
Generally, this communication is for informational purposes only
and it is not intended as an offer or solicitation for the purchase
or sale of any financial instrument or as an official confirmation
of any transaction. In the event you are receiving the offering
materials attached below related to your interest in hedge funds or
private equity, this communication may be intended as an offer or
solicitation for the purchase or sale of such fund(s).  All market
prices, data and other information are not warranted as to
completeness or accuracy and are subject to change without notice.
Any comments or statements made herein do not necessarily reflect
those of JPMorgan Chase & Co., its subsidiaries and affiliates.
This transmission may contain information that is privileged,
confidential, legally privileged, and/or exempt from disclosure
under applicable law. If you are not the intended recipient, you
are hereby notified that any disclosure, copying, distribution, or
use of the information contained herein (including any reliance
thereon) is STRICTLY PROHIBITED. Although this transmission and any
attachments are believed to be free of any virus or other defect
that might affect any computer system into which it is received and
opened, it is the responsibility of the recipient to ensure that it
is virus free and no responsibility is accepted by JPMorgan Chase &
Co., its subsidiaries and affiliates, as applicable, for any loss
or damage arising in any way from its use. If you received this
transmission in error, please immediately contact the sender and
destroy the material in its entirety, whether in electronic or hard
copy format. Thank you.
Please refer to http://www.jpmorgan.com/pages/disclosures for
disclosures relating to UK legal entities.
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe_at_subversion.tigris.org
For additional commands, e-mail: users-help_at_subversion.tigris.org