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Re: serf in 1.8

From: Stefan Küng <tortoisesvn_at_gmail.com>
Date: Tue, 13 Nov 2012 21:05:52 +0100

On 13.11.2012 21:03, Mark Phippard wrote:
> On Tue, Nov 13, 2012 at 2:48 PM, Mark Phippard <markphip_at_gmail.com> wrote:
>> On Tue, Nov 13, 2012 at 2:44 PM, Stefan Küng <tortoisesvn_at_gmail.com> wrote:
>>> On 13.11.2012 14:58, Mark Phippard wrote:
>>>
>>>> We did some testing in our lab, and the KeepAlive settings help a lot
>>>> here. Without any KeepAlive, then obviously every Serf request on
>>>> every connection needed to be re-authenticated. With KeepAlive on and
>>>> the connection limit set high enough then it was reduced to just the 4
>>>> connections that Serf opens to the server. So for our case, making
>>>> sure this was in place on our server, and then doing some more testing
>>>> to figure out the increases we needed to make in our backends was the
>>>> main issue to deal with.
>>>
>>>
>>> Did you do some testing with Windows domain authentication as well? Because
>>> last time I did some testing with that, KeepAlive doesn't do anything there.
>>> For some setups (for example, if the user GUEST is enabled on the domain
>>> controller) the re-authentication traffic is more than double the normal svn
>>> traffic.
>>
>> No, we only tested with our own mechanism to make sure that KeepAlive
>> would lessen the connection problem. With any mechanism, there would
>> have to be some kind of decent caching mechanism in place to not flood
>> the server with auth requests. I believe mod_ldap has one by default:
>>
>> http://httpd.apache.org/docs/2.2/mod/mod_ldap.html#ldapcacheentries
>>
>> Are you talking about mod_sspi? I do not know much about that module.
>
> Sounds like it depends on whether you have added:
>
> SSPIPerRequestAuth on
>
> It looks like that is off by default, which means the auth request is
> only done once per connection and KeepAlive should help limit that.
> If this directive is on, then every HTTP request will generate the
> SSPI authorization. That does seem to me like it would be a big
> problem when using Serf clients and performing a checkout.
>
> http://code.google.com/p/mod-auth-sspi/source/browse/trunk/src/mod_auth_sspi.c#68

That option helps a lot, yes.
But as I said: if the user GUEST is active on the domain controller, the
auth traffic still outweighs the normal svn traffic (using neon).
Haven't tested with serf though since I don't have access to such setups
anymore.
But from this discussion I wanted to ask if someone has tested this with
neon since I figure it might be worse than with neon.

Stefan

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Received on 2012-11-13 21:06:30 CET

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