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Posted to users@activemq.apache.org by superuser <pe...@automotive.com> on 2006/08/07 23:20:05 UTC
HA features
Hi i was trying to set up a HA broker config via Master/Slave according to
the following:
http://www.activemq.org/site/clustering.html
The fact that there is no automatic fail-back makes using this option *very*
difficult to support in a production environment. Specifically, once the
cluster has failed over to the secondary broker (which as documented seems
to work fine), the cluster cannot be recovered without the downtime required
to stop the SECONDARY, copy the datafiles, start the PRIMARY. This makes
routine maintenance of the PRIMARY impossible, because as soon as this
happens you are not HA without the required downtime & interruption of
service required to fail back to the primary.
I am not intimataly familiar with the internals of ActiveMQ, but it seems to
me that the easiest way to fix this would be some way of allowing the
primary to turn into the secondary (and visa-versa) when it comes back
online. This alone should be enough to allow the cluster to continue
servicing requests. If a the new primary (old secondary) then needs to be
taken down (maintenance, failure) it then swaps back to the secondary role.
Thoughts? Are there any current JIRA issues i should be tracking WRT this
functionality, or should i create a new request?
TIA for any help.
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Re: HA features
Posted by James Strachan <ja...@gmail.com>.
On 8/8/06, superuser <pe...@automotive.com> wrote:
>
> We would heavily prefer a shared-nothing architecture, and so for this reason
> are not considering a "shared backend" scenario.
>
> I had not considered a network of Master/Slave brokers, would this look, in
> a two machine configuration, something like:
>
> MACHINE1:
> MQ-A-PRIMARY
> MQ-B-BACKUP
>
> MACHINE2:
> MQ-A-BACKUP
> MQ-B-PRIMARY
>
> Where backups would be configured as normal and all servers would be
> configured as a network of brokers. Clients would have a connection string
> like
> "failover://(tcp://MQ-A-PRIMARY:PORT,tcp://MQ-B-PRIMARY:PORT,tcp://MQ-A-BACKUP:PORT,tcp://MQ-B-BACKUP:PORT)"
>
> Would this be a minimal HA cluster?
Yes - 4 brokers in 2 master-slave pairs with the broker M/S pairs
store-and-forwarding to each other.
> Incidentally, the "topology" section of the site was not necessarily crystal
> clear as to what a typical configuration would look like. I would think
> something like a list of use-cases, with a diagram of the topology and some
> lniks to .conf files for each would be VERY beneficial.
Agreed. We welcome contributions :)
http://incubator.apache.org/activemq/contributing.html
The website is a wiki so anyone can contribute documentation and diagrams..
http://incubator.apache.org/activemq/how-does-the-website-work.html
--
James
-------
http://radio.weblogs.com/0112098/
Re: HA features
Posted by superuser <pe...@automotive.com>.
We would heavily prefer a shared-nothing architecture, and so for this reason
are not considering a "shared backend" scenario.
I had not considered a network of Master/Slave brokers, would this look, in
a two machine configuration, something like:
MACHINE1:
MQ-A-PRIMARY
MQ-B-BACKUP
MACHINE2:
MQ-A-BACKUP
MQ-B-PRIMARY
Where backups would be configured as normal and all servers would be
configured as a network of brokers. Clients would have a connection string
like
"failover://(tcp://MQ-A-PRIMARY:PORT,tcp://MQ-B-PRIMARY:PORT,tcp://MQ-A-BACKUP:PORT,tcp://MQ-B-BACKUP:PORT)"
Would this be a minimal HA cluster?
Incidentally, the "topology" section of the site was not necessarily crystal
clear as to what a typical configuration would look like. I would think
something like a list of use-cases, with a diagram of the topology and some
lniks to .conf files for each would be VERY beneficial. IE, if you are
looking for HA, do X; if you are looking for highly scalable
read-infrastructure, do Y; etc. Just a suggestion, ignore at will ;-)
Thanks for the help regardless.
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View this message in context: http://www.nabble.com/HA-features---limitations-tf2069049.html#a5710116
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Re: HA features
Posted by James Strachan <ja...@gmail.com>.
On 8/7/06, superuser <pe...@automotive.com> wrote:
>
> Hi i was trying to set up a HA broker config via Master/Slave according to
> the following:
>
> http://www.activemq.org/site/clustering.html
>
> The fact that there is no automatic fail-back makes using this option *very*
> difficult to support in a production environment.
There is automatic failover support if you have a shared database or
shared file system...
http://incubator.apache.org/activemq/shared-file-system-master-slave.html
http://incubator.apache.org/activemq/jdbc-master-slave.html
> Specifically, once the
> cluster has failed over to the secondary broker (which as documented seems
> to work fine), the cluster cannot be recovered without the downtime required
> to stop the SECONDARY, copy the datafiles, start the PRIMARY. This makes
> routine maintenance of the PRIMARY impossible, because as soon as this
> happens you are not HA without the required downtime & interruption of
> service required to fail back to the primary.
You can have multiple master-slave pairs. So you can take down one
master/slave pair, clients will fail over to another masters/slave
pair
> I am not intimataly familiar with the internals of ActiveMQ, but it seems to
> me that the easiest way to fix this would be some way of allowing the
> primary to turn into the secondary (and visa-versa) when it comes back
> online. This alone should be enough to allow the cluster to continue
> servicing requests. If a the new primary (old secondary) then needs to be
> taken down (maintenance, failure) it then swaps back to the secondary role.
>
> Thoughts?
Sounds great - we just need some volunteers to design it, develop it
and test it :)
> Are there any current JIRA issues i should be tracking WRT this
> functionality, or should i create a new request?
I just did a quick query to check and no its not been raised in JIRA
yet. I've created one for you here...
http://issues.apache.org/activemq/browse/AMQ-869
--
James
-------
http://radio.weblogs.com/0112098/