The key problem with using svnsync for multiple Subversion repositories
distributed over a WAN is its reliance on a master-slave architecture. While
svnsync does provide the advantage of having local read-only repositories at
each of the remote development sites, only the master repository is
writeable. The master repository is then replicated to the read only slaves.
However, replication can place a significant load on the network and
servers. In addition, best practice requires the master server to be
unavailable for write operations while replication is taking place, in order
to avoid file corruption and other inconsistencies. For these reasons,
replication tends to happen on an infrequent basis, leaving the read-only
slave repositories that remote sites do their checkouts from out of sync
with the master much of the time. As a result, commit failures due to update
conflicts on the master repository can become a problem. In order to avoid
commit failures, developers at the slave repository sites have to do updates
over the WAN against the master Subversion repository before doing their
commits. This can negate most of the expected network performance and
developer productivity benefits of using svnsync in a distributed
development environment.
Other solutions such as svk do allow multiple repositories to be readable as
well as writeable, but there are no guarantees of consistency across the
repositories. A commit can succeed on a developer’s local repository where
there are no conflicts, and fail when it’s copied to other sites’
repositories due to update conflicts. This can make administration extremely
difficult.
WANdisco solves these problems by turning distributed Subversion
repositories into peers. All of the repositories are writeable, and
consistency across the repositories is guaranteed. WANdisco’s active-active
replication capabilities allow developers to work at LAN speed over the WAN
for both read and write operations, while keeping all of the repositories in
sync, in effect in real-time. WANdisco also provides self-healing
capabilities that automate disaster recovery after a network outage or
server failure.
http://www.wandisco.com http://www.wandisco.com
David Ferguson-2 wrote:
>
> Very interesting. So does this tool do the same job as WanDisco? I'd
> love
> to have true distributed repositories without the cost of WanDisco or the
> read-only limitations of svnsync.
>
> On 8/20/07, Chia-liang Kao <clkao@bestpractical.com> wrote:
>>
>> Hi all,
>>
>> I am pleased to announce version 1.0.0 of Pushmi, a subversion
>> repository replicate tool with read-write slaves.
>>
>> You can download pushmi at http://search.cpan.org/dist/Pushmi/
>>
>> For more information, please see:
>> http://search.cpan.org/dist/Pushmi/lib/Pushmi.pm
>>
>> There is also a mailing list at:
>> http://lists.bestpractical.com/cgi-bin/mailman/listinfo/pushmi-users
>>
>> Cheers,
>> CLK
>>
>>
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>
>
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Received on Fri Oct 5 05:27:06 2007