Re: [Resin-interest] Resin 4 Session Clustering - restart of triad servers
On 6/6/14, 2:51 PM, Burke, Brian wrote: > Hi Paul, >Thanks for the response. I did some more testing of my setup, and it > appears things are working as expected. I believe the source of my > confusion was the resin-admin UI: resin-admin/index.php?q=sessions&s=0 It > appears that after a restart, it doesn't show the count and session IDs of > the sessions that it has persisted to disk, and actually has available. When > I tested my scenarios in an actual app though, I can see session state is > maintained. That makes sense. The resin-admin tracks the in-memory sessions. It doesn't try to load them from disk. > >So there really are no cases where session data can be lost, as long as at > least one of the triad servers is running? And for a cluster of just 2 > servers, same situation, just need to make sure one server is always running > and things should be fine? In normal operation, it wouldn't be lost. When a triad server starts, it asks any other live triad servers for updates since the time it was down. It then saves the updates to disk. -- Scott > > Thanks, > -Brian > > > From: resin-interest-boun...@caucho.com [resin-interest-boun...@caucho.com] > On Behalf Of Paul Cowan [co...@caucho.com] > Sent: Thursday, June 05, 2014 9:53 AM > To: General Discussion for the Resin application server > Subject: Re: [Resin-interest] Resin 4 Session Clustering - restart of triad > servers > > On Jun 4, 2014, at 5:56 PM, Burke, Brian wrote: > >> A question related to session replication in resin 4.0 I’m using a cluster >> of 3 servers, therefore all three are triad servers. After a server is >> restarted, I see that the session objects that exist on the other two >> servers don’t get replicated to the restarted server until there is a >> request made for that session. With this behavior, I can’t restart these 3 >> servers in a rolling fashion, unless I wait at least ‘session-timeout’ >> between the restarts. > Hi Brian, > > The restarted triad server does keep a local copy on disk, but you are > partially correct - it will need to contact another triad server to verify it > has the most up-to-date version of the session data. > > I’m trying to understand why you think you need to wait session-time between > server restarts. I’m don’t think that is the case but if you are seeing > adverse behavior please supply details and that would help me determine if > it’s a bug or something else. As long as 1 triad server is up at any time > the triad state should be maintained properly. > > Thanks, > Paul > > >> Is there a way to force a restarting triad server to re-populate it’s store >> of sessions on restart? Or another way to handling planned rolling restarts >> of the triad servers in a more efficient manner? >> >> This is the current config in resin.xml, under the tag: >> >> >> >> >> >> >> >> >> Thanks, >> -Brian >> >> >> >> ___ >> resin-interest mailing list >> resin-interest@caucho.com >> http://maillist.caucho.com/mailman/listinfo/resin-interest > > ___ > resin-interest mailing list > resin-interest@caucho.com > http://maillist.caucho.com/mailman/listinfo/resin-interest > ___ > resin-interest mailing list > resin-interest@caucho.com > http://maillist.caucho.com/mailman/listinfo/resin-interest > ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
Re: [Resin-interest] Resin 4 Session Clustering - restart of triad servers
Hi Paul, Thanks for the response. I did some more testing of my setup, and it appears things are working as expected. I believe the source of my confusion was the resin-admin UI: resin-admin/index.php?q=sessions&s=0 It appears that after a restart, it doesn't show the count and session IDs of the sessions that it has persisted to disk, and actually has available. When I tested my scenarios in an actual app though, I can see session state is maintained. So there really are no cases where session data can be lost, as long as at least one of the triad servers is running? And for a cluster of just 2 servers, same situation, just need to make sure one server is always running and things should be fine? Thanks, -Brian From: resin-interest-boun...@caucho.com [resin-interest-boun...@caucho.com] On Behalf Of Paul Cowan [co...@caucho.com] Sent: Thursday, June 05, 2014 9:53 AM To: General Discussion for the Resin application server Subject: Re: [Resin-interest] Resin 4 Session Clustering - restart of triad servers On Jun 4, 2014, at 5:56 PM, Burke, Brian wrote: > A question related to session replication in resin 4.0 I’m using a cluster > of 3 servers, therefore all three are triad servers. After a server is > restarted, I see that the session objects that exist on the other two servers > don’t get replicated to the restarted server until there is a request made > for that session. With this behavior, I can’t restart these 3 servers in a > rolling fashion, unless I wait at least ‘session-timeout’ between the > restarts. Hi Brian, The restarted triad server does keep a local copy on disk, but you are partially correct - it will need to contact another triad server to verify it has the most up-to-date version of the session data. I’m trying to understand why you think you need to wait session-time between server restarts. I’m don’t think that is the case but if you are seeing adverse behavior please supply details and that would help me determine if it’s a bug or something else. As long as 1 triad server is up at any time the triad state should be maintained properly. Thanks, Paul > > Is there a way to force a restarting triad server to re-populate it’s store > of sessions on restart? Or another way to handling planned rolling restarts > of the triad servers in a more efficient manner? > > This is the current config in resin.xml, under the tag: > > > > > > > > > Thanks, > -Brian > > > > ___ > resin-interest mailing list > resin-interest@caucho.com > http://maillist.caucho.com/mailman/listinfo/resin-interest ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
Re: [Resin-interest] Resin 4 Session Clustering - restart of triad servers
On Jun 4, 2014, at 5:56 PM, Burke, Brian wrote: > A question related to session replication in resin 4.0 I’m using a cluster > of 3 servers, therefore all three are triad servers. After a server is > restarted, I see that the session objects that exist on the other two servers > don’t get replicated to the restarted server until there is a request made > for that session. With this behavior, I can’t restart these 3 servers in a > rolling fashion, unless I wait at least ‘session-timeout’ between the > restarts. Hi Brian, The restarted triad server does keep a local copy on disk, but you are partially correct - it will need to contact another triad server to verify it has the most up-to-date version of the session data. I’m trying to understand why you think you need to wait session-time between server restarts. I’m don’t think that is the case but if you are seeing adverse behavior please supply details and that would help me determine if it’s a bug or something else. As long as 1 triad server is up at any time the triad state should be maintained properly. Thanks, Paul > > Is there a way to force a restarting triad server to re-populate it’s store > of sessions on restart? Or another way to handling planned rolling restarts > of the triad servers in a more efficient manner? > > This is the current config in resin.xml, under the tag: > > > > > > > > > Thanks, > -Brian > > > > ___ > resin-interest mailing list > resin-interest@caucho.com > http://maillist.caucho.com/mailman/listinfo/resin-interest ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
[Resin-interest] Resin 4 Session Clustering - restart of triad servers
A question related to session replication in resin 4.0 I’m using a cluster of 3 servers, therefore all three are triad servers. After a server is restarted, I see that the session objects that exist on the other two servers don’t get replicated to the restarted server until there is a request made for that session. With this behavior, I can’t restart these 3 servers in a rolling fashion, unless I wait at least ‘session-timeout’ between the restarts. Is there a way to force a restarting triad server to re-populate it’s store of sessions on restart? Or another way to handling planned rolling restarts of the triad servers in a more efficient manner? This is the current config in resin.xml, under the tag: Thanks, -Brian ___ resin-interest mailing list resin-interest@caucho.com http://maillist.caucho.com/mailman/listinfo/resin-interest
