Skip to Content.
Sympa Menu

grouper-users - RE: [grouper-users] Grouper and database failover

Subject: Grouper Users - Open Discussion List

List archive

RE: [grouper-users] Grouper and database failover

Chronological Thread 
  • From: Chris Hyzer <>
  • To: "William G. Thompson, Jr." <>, Peter DiCamillo <>
  • Cc: "" <>
  • Subject: RE: [grouper-users] Grouper and database failover
  • Date: Thu, 9 Jun 2011 14:22:42 -0400
  • Accept-language: en-US
  • Acceptlanguage: en-US

Let me say another thing... if you get the latest oracle driver jar, and
configure the rac nodes in the connect string of, e.g.

hibernate.connection.url =

<note, you will need to adjust the failover settings etc>

Maybe you need to adjust the c3p0 settings so the connections timeout after
some short period of time (1 minute?)

Then I would think when a rac node went down, then the driver would use the
other node. However, on our non-grouper systems, we tried this (maybe it was
our c3p0 settings...), but it didn't really work when a rac node failed. The
disadvantage of this is there is not the ONS to proactively tell the driver
to take a node out of the pool, however, the hardcoded lists is better then
nothing if ONS is not available in Grouper yet. Bottom line, it might be
worth a shot to try something like this and see if it works until ONS :)


-----Original Message-----
From: Chris Hyzer
Sent: Thursday, June 09, 2011 9:24 AM
To: 'William G. Thompson, Jr.'; Peter DiCamillo

Subject: RE: [grouper-users] Grouper and database failover

> Curious if you (or anyone else) has also consider a NoSQL option for
> this? OrientDB looks particularly interesting...

The Grouper API heavily depends on a relational database...

> We're looking at the possibility of configuring Grouper so we can use
> database failover. We'd like to be able to keep Grouper up during database
> maintenance, and also in disaster recover situations. We use Grouper with an
> Oracle database and with tomcat. We also have some java programs which use
> the Grouper API and do not run under tomcat.
> I don't have extensive knowledge of Oracle or jdbc, but some quick Google
> research suggests that this may be possible, and the recommended method
> involves using Oracle's Fast Connection Failover mechanism.
> Does anyone have experience with Grouper and database failover? Are there
> known reasons why it could or could not be made to work?

Here is my understanding... FCF requires either oracle's db pool where you
configure the ONS and that tells it what servers are in the pool, and which
ones to take out when they go down. You can use FCF with c3p0 (our db pool)
if you use the "simple fan" where you write code to listen for ons events and
adjust the pool accordingly (sounds less appealing to me). Right now Grouper
uses c3p0 and a DB driver, so if that is all that is needed, configure it as
you like. If you are using ONS, I think we will need to make the pool type
configurable, and do some work to make sure it is ONS compatible. Penn is
probably going to need this at some point, and we use ONS for other things,
so we will add this into Grouper at some point if someone else doesn't do it
sooner :)

Btw, we are just using hibernate with c3p0 in hibernate, maybe there is a way
to adjust the to use fcf without changing code
(I wouldn't bet on it, but maybe) :)


Archive powered by MHonArc 2.6.16.

Top of Page