[Linux-cluster] Red Hat Cluster Service and Informix with 1.5 GB memory allocation

[Lon Hohberger]

On Thu, 2006-08-10 at 13:41 +0530, Subodh Bhagat wrote:
> Dear all,
> 
> This issue is with one of our major customers, IBM Global Services.
> They are implementing a 3 node cluster and configuring Informix
> database for failover. The specifications of the three nodes are as
> follows:
> 
> ADBM01      2.4.21-40.ELsmp i686              AS release 3 (Taroon
> Update 8)      clumanager-1.2.31-1-i386
> ADBM02      2.4.21-40.ELsmp i686              AS release 3 (Taroon
> Update 8)      clumanager-1.2.31-1-i386
> ADBM03      2.4.21-40.ELhugemem  i686    AS release 3 (Taroon Update
> 8)      clumanager-1.2.26.1-1-i386
> 
> Informix version: IBM Informix Dynamic Server 10.00.UC4 On Linux Intel
> 
> Informix runs with over 1.8GB MEM allocated to it on the server when
> the clustering agents are turned off. Also it works with Mem
> allocation of less that 1.5 GB in cluster environment. But when in
> cluster environment, the node is rebooted if  >=1.5 GB is allocated. 
> 
> At Informix end, the SHMBASE parameter would help only if there was a
> memory allocation issue between Linux and Informix. But as Informix
> runs with over 1.8GB MEM allocated to it on the server when the
> clustering agents are turned off, altering SHMBASE may not help
> resolving this issue. The issue most definitely be between the Red Hat
> Cluster Service and Informix with a high mem allocation.
> 
> * We have suggested the customer to setup all the nodes in cluster as
> identical with respect to the kernel version and cluster suite
> versions and OS versions.

RHCS3 supports rolling upgrade, so there shouldn't be an issue with the
1.2.26.1 + 1.2.31 versions being mixed.  There certainly shouldn't be
though.

> * Any idea, what else can be done here?

You can try setting realtime priority in RHCS; see the cludb man page.
Also, increase the failover time.  Both will decrease the chance that
clumanager gets a 'false' transition.

-- Lon