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Posted to users@wicket.apache.org by mchack <mc...@cisco.com> on 2007/09/28 01:23:24 UTC
Clustering Question - Can the 2nd Level Page Cache be shared in a
clustered filesystem configuration?
I am deploying my application in a clustered environment. Eliminating session
sticky load balancing would be an advantage for me. Session data is already
replicated in a clustered environment. Are the mechanics in place to share
the Page Cache with other machines if I use a clustered file system that
allows concurrent access in this way providing non sticky LB across the
cluster?
-Mike
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Re: Clustering Question - Can the 2nd Level Page Cache be shared in a clustered filesystem configuration?
Posted by Matej Knopp <ma...@gmail.com>.
Ah, I guess i understood the question a bit wrong then. Sticky mode is
preferred with wicket, as we use redirect to buffer render strategy by
default. Also from a performance standpoint, I'd recommend sticky
mode.
As for the page store, what i suggested was a merely performance
improvement. Since you 'd have clustered disk page store, there's no
need to replicate the last accessed page over the cluster using the
standard session replication. So what my suggestion would do is that
you'd have only a _very_ small (couple of hundreds of bytes)
replicated session state.
-Matej
On 9/28/07, mchack <mc...@cisco.com> wrote:
>
> While looking at load balancer options I was trying to see if the non session
> sticky mode was an option. Obviously there are a bunch of issues I hadn't
> considered such as threading mode and concurrent client access. It is clear
> I will stick with the original plan of session sticky mode.
>
> -mike
>
>
> Johan Compagner wrote:
> >
> > Why don't you want session sticky load balancing?
> >
> > How does none sticky sessions work then? If there are 2 request comming in
> > then wicket makes sure
> > that the page is access in one thread. So that the page is not changed by
> > 2
> > threads at the same time
> > Does your application server lock over the nodes when there are 2 or more
> > request comming in from the same client?
> > If not how does it then sync up again? How does it "merge" the pages?
> >
> > johan
> >
> >
> >
> > On 9/28/07, mchack <mc...@cisco.com> wrote:
> >>
> >>
> >> I am deploying my application in a clustered environment. Eliminating
> >> session
> >> sticky load balancing would be an advantage for me. Session data is
> >> already
> >> replicated in a clustered environment. Are the mechanics in place to
> >> share
> >> the Page Cache with other machines if I use a clustered file system that
> >> allows concurrent access in this way providing non sticky LB across the
> >> cluster?
> >>
> >> -Mike
> >> --
> >> View this message in context:
> >> http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12932067
> >> Sent from the Wicket - User mailing list archive at Nabble.com.
> >>
> >>
> >> ---------------------------------------------------------------------
> >> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
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> >>
> >>
> >
> >
>
> --
> View this message in context: http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12937318
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Re: Clustering Question - Can the 2nd Level Page Cache be shared in
a clustered filesystem configuration?
Posted by mchack <mc...@cisco.com>.
While looking at load balancer options I was trying to see if the non session
sticky mode was an option. Obviously there are a bunch of issues I hadn't
considered such as threading mode and concurrent client access. It is clear
I will stick with the original plan of session sticky mode.
-mike
Johan Compagner wrote:
>
> Why don't you want session sticky load balancing?
>
> How does none sticky sessions work then? If there are 2 request comming in
> then wicket makes sure
> that the page is access in one thread. So that the page is not changed by
> 2
> threads at the same time
> Does your application server lock over the nodes when there are 2 or more
> request comming in from the same client?
> If not how does it then sync up again? How does it "merge" the pages?
>
> johan
>
>
>
> On 9/28/07, mchack <mc...@cisco.com> wrote:
>>
>>
>> I am deploying my application in a clustered environment. Eliminating
>> session
>> sticky load balancing would be an advantage for me. Session data is
>> already
>> replicated in a clustered environment. Are the mechanics in place to
>> share
>> the Page Cache with other machines if I use a clustered file system that
>> allows concurrent access in this way providing non sticky LB across the
>> cluster?
>>
>> -Mike
>> --
>> View this message in context:
>> http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12932067
>> Sent from the Wicket - User mailing list archive at Nabble.com.
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
>> For additional commands, e-mail: users-help@wicket.apache.org
>>
>>
>
>
--
View this message in context: http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12937318
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Re: Clustering Question - Can the 2nd Level Page Cache be shared in a clustered filesystem configuration?
Posted by Johan Compagner <jc...@gmail.com>.
Why don't you want session sticky load balancing?
How does none sticky sessions work then? If there are 2 request comming in
then wicket makes sure
that the page is access in one thread. So that the page is not changed by 2
threads at the same time
Does your application server lock over the nodes when there are 2 or more
request comming in from the same client?
If not how does it then sync up again? How does it "merge" the pages?
johan
On 9/28/07, mchack <mc...@cisco.com> wrote:
>
>
> I am deploying my application in a clustered environment. Eliminating
> session
> sticky load balancing would be an advantage for me. Session data is
> already
> replicated in a clustered environment. Are the mechanics in place to share
> the Page Cache with other machines if I use a clustered file system that
> allows concurrent access in this way providing non sticky LB across the
> cluster?
>
> -Mike
> --
> View this message in context:
> http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12932067
> Sent from the Wicket - User mailing list archive at Nabble.com.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
> For additional commands, e-mail: users-help@wicket.apache.org
>
>
Re: Clustering Question - Can the 2nd Level Page Cache be shared in a clustered filesystem configuration?
Posted by Johan Compagner <jc...@gmail.com>.
"Serialize to the session" is a completely wrong statement
Nothing is serialized into the session, it is put in the session. and then
the application server
can serialize the session to other nodes or to disk or what ever.
If you have an standard app server and you don't have multiply nodes and you
don't restart
the server then normally the pages are never serialized that are kept in the
session
We do serialize the pages besides the session. And matej made some
optimizations that
when the server does cluster (serialize) that the page is only serialized
once and it tries
to reuse that byte instance.
johan
On 9/28/07, mchack <mc...@cisco.com> wrote:
>
>
> I am not sure I understand correctly. :)
>
> I thought the current page was serialized to the session and that the
> other
> pages or views were stored to the filesystem. So my question was really,
> if
> the filesystem where temporary pages are stored is shared, would Wicket be
> immune to requests coming in to random servers in the cluster. I was
> hoping
> that it might be possible to do a dumb load balancing arrangement. I am
> not
> totally clear on the whole page lifecycle, so hopefully my question is not
> completely out in left field.
>
> -Mike
>
>
>
> Matej Knopp-2 wrote:
> >
> > Hi,
> >
> > if I understand correctly, you want to disable page serialization on
> > session replication, as the filesystem where the page store stores
> > temporary pages is accessible from each node in cluster?
> >
> > There is a way to achieve it, just create your own page store
> > extending from DiskPageStore and make it implement the
> > SecondLevelCacheSessionStore.IClusteredPageStore interface. Just
> > implementing this interface will cause that the last accessed page
> > will not be replicated across cluster.
> >
> > -Matej
> >
> >
> --
> View this message in context:
> http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12933068
> Sent from the Wicket - User mailing list archive at Nabble.com.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
> For additional commands, e-mail: users-help@wicket.apache.org
>
>
Re: Clustering Question - Can the 2nd Level Page Cache be shared in
a clustered filesystem configuration?
Posted by mchack <mc...@cisco.com>.
I am not sure I understand correctly. :)
I thought the current page was serialized to the session and that the other
pages or views were stored to the filesystem. So my question was really, if
the filesystem where temporary pages are stored is shared, would Wicket be
immune to requests coming in to random servers in the cluster. I was hoping
that it might be possible to do a dumb load balancing arrangement. I am not
totally clear on the whole page lifecycle, so hopefully my question is not
completely out in left field.
-Mike
Matej Knopp-2 wrote:
>
> Hi,
>
> if I understand correctly, you want to disable page serialization on
> session replication, as the filesystem where the page store stores
> temporary pages is accessible from each node in cluster?
>
> There is a way to achieve it, just create your own page store
> extending from DiskPageStore and make it implement the
> SecondLevelCacheSessionStore.IClusteredPageStore interface. Just
> implementing this interface will cause that the last accessed page
> will not be replicated across cluster.
>
> -Matej
>
>
--
View this message in context: http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12933068
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Re: Clustering Question - Can the 2nd Level Page Cache be shared in a clustered filesystem configuration?
Posted by Matej Knopp <ma...@gmail.com>.
Hi,
if I understand correctly, you want to disable page serialization on
session replication, as the filesystem where the page store stores
temporary pages is accessible from each node in cluster?
There is a way to achieve it, just create your own page store
extending from DiskPageStore and make it implement the
SecondLevelCacheSessionStore.IClusteredPageStore interface. Just
implementing this interface will cause that the last accessed page
will not be replicated across cluster.
-Matej
On 9/28/07, mchack <mc...@cisco.com> wrote:
>
> I am deploying my application in a clustered environment. Eliminating session
> sticky load balancing would be an advantage for me. Session data is already
> replicated in a clustered environment. Are the mechanics in place to share
> the Page Cache with other machines if I use a clustered file system that
> allows concurrent access in this way providing non sticky LB across the
> cluster?
>
> -Mike
> --
> View this message in context: http://www.nabble.com/Clustering-Question---Can-the-2nd-Level-Page-Cache-be-shared-in-a-clustered-filesystem-configuration--tf4531607.html#a12932067
> Sent from the Wicket - User mailing list archive at Nabble.com.
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscribe@wicket.apache.org
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>
>
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