HTTPSession replication to *each* node?

[joachimm]

In the Clustering doc, there is a comment about
the replication of Session Beans to each node
in a cluster, and how this would not be desirable
in a large cluster. The solution is to use
sub-partition, which the RMI proxies seem to know
how to deal with.

This doesn't seem to apply to HTTPSession replication,
which would be a major drawback. Could someone comment
on how HTTPSession clustering works in a large cluster?
Say instead of 10 nodes, you have 80? (4 processes
per server, 20 servers). If I set up 20 sub-partitions,
what happens if all four nodes in my current
sub-partition go down? Does mod_jk understand
sub-partitions? (I doubt it)

Weblogic implements a Primary/Secondary session backup
server sort of design, and it seems like a more
efficient way to handle large clusters. It is
obviously harder to implement this way, and more
vulnerable to single-point-of-failure issues, but it
may improve performance (at least network perf...)
for the cluster as a whole.

Thanks

[slaboure]

Yes, sub-partition is currently not handled for both SFSB and HttpSessions. Code is there but is dangling (following the implementation of detached invokers).

The set of features you describe is on the todo list for 4.0.

Cheers,


sacha

[echofloripa]

when the sub-partition will be available??? the question can be, when 4.0 will be ready, about javaone???

[jules]

Emerson,

If you are using Jetty, in a recent JBoss, with JGStore as your distribution mechanism (it's the default), then there is an attribute that you can set to compartmentalise nodes into subclusters.

Limitations to the current state of the impl are :

1. sticky sessions are not yet supported - distribution is synchronous.

2. distribution is only done on an explicit mutation of the session - i.e. putting a reference to a mutable object into the session and then fiddling with that object will not cause it to be distributed. In this case call setAttribute(key,val) again when you want distribution.

3. seLastAccessedTime() is distributed every time - inefficient. I have various plans for batching these calls up and only distributing them every minute or so - NYI.

N.B.

Distribution is done via JavaGroups, on an attribute-by-attribute basis...

HttpSession clusters/channels and JBoss clusters/channels are orthogonal.

Is this of any use to you ?


Jules

[echofloripa]

> you are using Jetty, in a recent JBoss, with JGStore as >your distribution mechanism (it's the default), then >there is an attribute that you can set to >compartmentalise nodes into subclusters.

recent jboss, you mean 3.0.6?
is there some where I can find a how-to to configure this??

>Limitations to the current state of the impl are :

>1. sticky sessions are not yet supported - distribution >is synchronous.

why sticky session is not supported, isn't the load-balancer (mod_jk in my case) that will choose the server?? sorry for my ignorancem, but what being synchronous has to do with this?? could you expand on this?

>2. distribution is only done on an explicit mutation of >the session - i.e. putting a reference to a mutable >object into the session and then fiddling with that >object will not cause it to be distributed. In this case >call setAttribute(key,val) again when you want >distribution.

ok. the framework could nest into the object (using equals, for example) to see if has changed, isn't?

>3. seLastAccessedTime() is distributed every time - >inefficient. I have various plans for batching these >calls up and only distributing them every minute or so - >NYI.

ok...

>N.B.

>Distribution is done via JavaGroups, on an >attribute-by-attribute basis...

>HttpSession clusters/channels and JBoss clusters/channels >are orthogonal.

you mean that for SFSB and http-session are distributed in the same way? BTW, are SFSB currently using sub-particions?? I undertood, for what i read in some threads, that sub-particions will be available (either in httpsessions ou SFSB) when detached-invokers where ready??
could you tell me how is the current state of this??

>Is this of any use to you ?

of course, thanks a lot.

Me and a coleague are making a article for a brazillian java magazine about clustering with focus on JBoss, so i'd like to give an idea about what are the future features of jboss related to cluster.

could you tell me any other future feature?

Thanks a lot

Emerson

[echofloripa]

> you are using Jetty, in a recent JBoss, with JGStore as >your distribution mechanism (it's the default), then >there is an attribute that you can set to >compartmentalise nodes into subclusters.

recent jboss, you mean 3.0.6?
is there some where I can find a how-to to configure this??

>Limitations to the current state of the impl are :

>1. sticky sessions are not yet supported - distribution >is synchronous.

why sticky session is not supported, isn't the load-balancer (mod_jk in my case) that will choose the server?? sorry for my ignorancem, but what being synchronous has to do with this?? could you expand on this?

>2. distribution is only done on an explicit mutation of >the session - i.e. putting a reference to a mutable >object into the session and then fiddling with that >object will not cause it to be distributed. In this case >call setAttribute(key,val) again when you want >distribution.

ok. the framework could nest into the object (using equals, for example) to see if has changed, isn't?

>3. seLastAccessedTime() is distributed every time - >inefficient. I have various plans for batching these >calls up and only distributing them every minute or so - >NYI.

ok...

>N.B.

>Distribution is done via JavaGroups, on an >attribute-by-attribute basis...

>HttpSession clusters/channels and JBoss clusters/channels >are orthogonal.

you mean that for SFSB and http-session are distributed in the same way? BTW, are SFSB currently using sub-particions?? I undertood, for what i read in some threads, that sub-particions will be available (either in httpsessions ou SFSB) when detached-invokers where ready??
could you tell me how is the current state of this??

>Is this of any use to you ?

of course, thanks a lot.

Me and a coleague are making a article for a brazillian java magazine about clustering with focus on JBoss, so i'd like to give an idea about what are the future features of jboss related to cluster.

could you tell me any other future feature?

Thanks a lot

Emerson

[echofloripa]

> you are using Jetty, in a recent JBoss, with JGStore as >your distribution mechanism (it's the default), then >there is an attribute that you can set to >compartmentalise nodes into subclusters.

recent jboss, you mean 3.0.6?
is there some where I can find a how-to to configure this??

>Limitations to the current state of the impl are :

>1. sticky sessions are not yet supported - distribution >is synchronous.

why sticky session is not supported, isn't the load-balancer (mod_jk in my case) that will choose the server?? sorry for my ignorancem, but what being synchronous has to do with this?? could you expand on this?

>2. distribution is only done on an explicit mutation of >the session - i.e. putting a reference to a mutable >object into the session and then fiddling with that >object will not cause it to be distributed. In this case >call setAttribute(key,val) again when you want >distribution.

ok. the framework could nest into the object (using equals, for example) to see if has changed, isn't?

>3. seLastAccessedTime() is distributed every time - >inefficient. I have various plans for batching these >calls up and only distributing them every minute or so - >NYI.

ok...

>N.B.

>Distribution is done via JavaGroups, on an >attribute-by-attribute basis...

>HttpSession clusters/channels and JBoss clusters/channels >are orthogonal.

you mean that for SFSB and http-session are distributed in the same way? BTW, are SFSB currently using sub-particions?? I undertood, for what i read in some threads, that sub-particions will be available (either in httpsessions ou SFSB) when detached-invokers where ready??
could you tell me how is the current state of this??

>Is this of any use to you ?

of course, thanks a lot.

Me and a coleague are making a article for a brazillian java magazine about clustering with focus on JBoss, so i'd like to give an idea about what are the future features of jboss related to cluster.

could you tell me any other future feature?

Thanks a lot

Emerson

[echofloripa]

> you are using Jetty, in a recent JBoss, with JGStore as >your distribution mechanism (it's the default), then >there is an attribute that you can set to >compartmentalise nodes into subclusters.

recent jboss, you mean 3.0.6?
is there some where I can find a how-to to configure this??

>Limitations to the current state of the impl are :

>1. sticky sessions are not yet supported - distribution >is synchronous.

why sticky session is not supported, isn't the load-balancer (mod_jk in my case) that will choose the server?? sorry for my ignorancem, but what
being synchronous has to do with this?? could you expand on this?

>2. distribution is only done on an explicit mutation of >the session -i.e. putting a reference to a mutable >object into the session and then fiddling with that >object will not cause it to be distributed. In this
>case call setAttribute(key,val) again when you want >distribution.

ok. the framework could nest into the object (using equals, for example)
to see if has changed, isn't?

>3. seLastAccessedTime() is distributed every time - >inefficient.have various plans for batching these
>calls up and only distributing them every minute or so - >NYI.

ok...

>N.B.

>Distribution is done via JavaGroups, on an
>attribute-by-attribute basis...

>HttpSession clusters/channels and JBoss >clusters/channels are orthogonal.

you mean that for SFSB and http-session are distributed in the same way?
BTW, are SFSB currently using sub-particions?? I undertood, for what i
read in some threads, that sub-particions will be available (either in
httpsessions ou SFSB) when detached-invokers where ready??
could you tell me how is the current state of this??

>Is this of any use to you ?

of course, thanks a lot.

Me and a coleague are making a article for a brazillian java magazine
about clustering with focus on JBoss, so i'd like to give an idea about
what are the future features of jboss related to cluster.

could you tell me any other future feature?

Thanks a lot

Emerson

[echofloripa]

my reply doens't work.... testing to see if a short msg goes...

[echofloripa]

> you are using Jetty, in a recent JBoss, with JGStore as >your distribution mechanism (it's the default), then >there is an attribute that you can set to >compartmentalise nodes into subclusters.

recent jboss, you mean 3.0.6?
is there some where I can find a how-to to configure this??

>Limitations to the current state of the impl are :

>1. sticky sessions are not yet supported - distribution >is synchronous.

why sticky session is not supported, isn't the load-balancer (mod_jk in my case) that will choose the server?? sorry for my ignorancem, but what
being synchronous has to do with this?? could you expand on this?

>2. distribution is only done on an explicit mutation of >the session -i.e. putting a reference to a mutable >object into the session and then fiddling with that >object will not cause it to be distributed. In this
>case call setAttribute(key,val) again when you want >distribution.

ok. the framework could nest into the object (using equals, for example)
to see if has changed, isn't?

>3. seLastAccessedTime() is distributed every time - >inefficient.have various plans for batching these
>calls up and only distributing them every minute or so - >NYI.

ok...

>N.B.

>Distribution is done via JavaGroups, on an
>attribute-by-attribute basis...

>HttpSession clusters/channels and JBoss >clusters/channels are orthogonal.

you mean that for SFSB and http-session are distributed in the same way?
BTW, are SFSB currently using sub-particions?? I undertood, for what i
read in some threads, that sub-particions will be available (either in
httpsessions ou SFSB) when detached-invokers where ready??
could you tell me how is the current state of this??

>Is this of any use to you ?

of course, thanks a lot.

Me and a coleague are making a article for a brazillian java magazine
about clustering with focus on JBoss, so i'd like to give an idea about
what are the future features of jboss related to cluster.

could you tell me any other future feature?

Thanks a lot

[echofloripa]

sorry, but my message was not appearing at the thread, just now it did show up (the three of them :)