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Posted to users@subversion.apache.org by Rajesh Patwardhan <rp...@westjet.com> on 2006/10/04 16:58:20 UTC
Subversion in Cluster mode tips?
Hi,
I was wondering how subversion repositories can be configured in a
clustered mode. We will have minimal writes to this repository but lots
of read requests and hence we need to put it in a cluster mode.
Examples \ pointers on Windows or Unix would be gratefully accepted.
Thank you very much in advance for your time.
Regards,
Rajesh
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Re: Subversion in Cluster mode tips?
Posted by Tom Mornini <tm...@engineyard.com>.
I too, assume that's what he meant, but it's patently untrue.
We're running a cluster of Apache/mod_dav_svn servers that are
load balanced and access repositories on a RHCS GFS filesytem,
and it works beautifully.
On Oct 4, 2006, at 1:59 PM, Mark wrote:
> I assume what he means is that you cannot have a single virtual
> presence be a subversion front end to multiple subversion back ends
> and that virtual server can be moved from one physical backend to t he
> next. Isn't that the basic definition of clustering? One could write
> an agent for Veritas Cluster Server, though, to accomplish this.
>
> On 10/4/06, Tom Mornini <tm...@infomania.com> wrote:
>> On Oct 4, 2006, at 12:09 PM, Johnathan Gifford wrote:
>>
>> > You can't cluster Subversion.
>>
>> What do you mean by this?
>>
>> I think that may be too broad a statement in and of itself.
>>
>> --
>> -- Tom Mornini
>>
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>>
>
>
> --
> Mark
> "Blessed is he who finds happiness in his own foolishness, for he will
> always be happy."
>
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Re: Subversion in Cluster mode tips?
Posted by Mark <ma...@mitsein.net>.
I assume what he means is that you cannot have a single virtual
presence be a subversion front end to multiple subversion back ends
and that virtual server can be moved from one physical backend to t he
next. Isn't that the basic definition of clustering? One could write
an agent for Veritas Cluster Server, though, to accomplish this.
On 10/4/06, Tom Mornini <tm...@infomania.com> wrote:
> On Oct 4, 2006, at 12:09 PM, Johnathan Gifford wrote:
>
> > You can't cluster Subversion.
>
> What do you mean by this?
>
> I think that may be too broad a statement in and of itself.
>
> --
> -- Tom Mornini
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@subversion.tigris.org
> For additional commands, e-mail: users-help@subversion.tigris.org
>
>
--
Mark
"Blessed is he who finds happiness in his own foolishness, for he will
always be happy."
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Re: Subversion in Cluster mode tips?
Posted by Tom Mornini <tm...@engineyard.com>.
On Oct 4, 2006, at 9:03 PM, Ryan Schmidt wrote:
> On Oct 4, 2006, at 16:42, Johnathan Gifford wrote:
>
> I was under the impression that FSFS and NFS would work fine together.
>
> However, what about using a storage-attached network (SAN) like
> Apple's Xsan? These kinds of volumes can be mounted simultaneously
> on multiple servers and read from and written to without conflict.
> Shouldn't a bank of servers with e.g. round-robin DNS and Apache 2
> and mod_dav_svn and repositories stored on such a SAN be able to
> provide load-balanced access to these repositories?
That's what we're doing here with AoE and GFS, and it's working fine.
--
-- Tom Mornini
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Re: Subversion in Cluster mode tips?
Posted by Ryan Schmidt <su...@ryandesign.com>.
On Oct 4, 2006, at 16:42, Johnathan Gifford wrote:
> But the real question about 'clustering' is, can you have multiple
> Apache/Subversion servers that all have access to the same repository?
> That is each Apache/Subversion server would mount a drive through
> NFS to
> the repository. Now, you cannot do this with a Berkely DB power
> repository because it cannot exist on a remote file system such NFS.
> Now what about a FSFS power repository? You can install it on a NFS,
> but the svn book says you shouldn't. And it does not say anything
> about
> having multiple Apache/Subversion services accessing a single
> repository
> over NFS. If you can do that, then you could cluster the 'services'
> part of Subversion on separate servers with Apache as the cluster
> point
> providing the single point of access. This is the setup that has
> me the
> most curious if it would work. Anyone doing this without any
> problems?
I was under the impression that FSFS and NFS would work fine together.
However, what about using a storage-attached network (SAN) like
Apple's Xsan? These kinds of volumes can be mounted simultaneously on
multiple servers and read from and written to without conflict.
Shouldn't a bank of servers with e.g. round-robin DNS and Apache 2
and mod_dav_svn and repositories stored on such a SAN be able to
provide load-balanced access to these repositories?
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Re: Subversion in Cluster mode tips?
Posted by Johnathan Gifford <jg...@wernervas.com>.
Okay, a bit of refinement: You cannot cluster a Subversion
repository.
There can only be one copy of the repository. So you cannot have two
(or more) Subversion 'servers' with there own active copy of the
repository that are synchronized automatically among all servers. So
clustering in the sense of a web application server like ColdFusion,
Java, or .NET doesn't exist. These types of cluster are generally
accessed through a single point of reference and all requests are
balanced across all available servers.
You can have one active repository and multiple mirrored (read-only)
repositories with Subversion 1.4.0 and the snvsync functionality. But,
this keeps you from committing changes back to the mirrored repository.
And there is not a single point of access to the repository because
there are multiple copies of the repository, but only one point of
access is writable. Since there are not multiple access points, this is
not clustering.
Now, if you consider a fail-over system as a 'cluster', this can be
done. This is because both servers have Subversion installed, but only
one has control of the repository. When the primary server fails to
respond, the second server can gain control of the repository and then
act upon requests to the repository. The problem here is that you
cannot balance the load (requests) between multiple servers because all
secondary servers are only lying in wait for their primary server to not
respond so it can take over. So, I do not consider fail-over system as
a true cluster.
But the real question about 'clustering' is, can you have multiple
Apache/Subversion servers that all have access to the same repository?
That is each Apache/Subversion server would mount a drive through NFS to
the repository. Now, you cannot do this with a Berkely DB power
repository because it cannot exist on a remote file system such NFS.
Now what about a FSFS power repository? You can install it on a NFS,
but the svn book says you shouldn't. And it does not say anything about
having multiple Apache/Subversion services accessing a single repository
over NFS. If you can do that, then you could cluster the 'services'
part of Subversion on separate servers with Apache as the cluster point
providing the single point of access. This is the setup that has me the
most curious if it would work. Anyone doing this without any problems?
Johnathan
>>> On Wed, Oct 4, 2006 at 2:58 PM, in message
<C5...@infomania.com>, Tom Mornini
<tm...@infomania.com> wrote:
> On Oct 4, 2006, at 12:09 PM, Johnathan Gifford wrote:
>
>> You can't cluster Subversion.
>
> What do you mean by this?
>
> I think that may be too broad a statement in and of itself.
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Re: Subversion in Cluster mode tips?
Posted by Tom Mornini <tm...@infomania.com>.
On Oct 4, 2006, at 12:09 PM, Johnathan Gifford wrote:
> You can't cluster Subversion.
What do you mean by this?
I think that may be too broad a statement in and of itself.
--
-- Tom Mornini
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Re: Subversion in Cluster mode tips?
Posted by Johnathan Gifford <jg...@wernervas.com>.
Rajesh
You can't cluster Subversion. However, if all those reads are in the
form of an export or working copy checkouts that will never be committed
back to the repository, you might consider svnsync and to make mirrors
of your repositories.
Info about svnsync can be found at:
http://svn.collab.net/repos/svn/trunk/notes/svnsync.txt
Good Luck,
Johnathan
>>> On Wed, Oct 4, 2006 at 11:58 AM, in message
<94...@SRVHQMAILC01B.westjet.priv>,
"Rajesh
Patwardhan" <rp...@westjet.com> wrote:
> Hi,
> I was wondering how subversion repositories can be configured in a
> clustered mode. We will have minimal writes to this repository but
lots
> of read requests and hence we need to put it in a cluster mode.
> Examples \ pointers on Windows or Unix would be gratefully accepted.
> Thank you very much in advance for your time.
> Regards,
> Rajesh
>
>
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