1.) When you guys are installing HACMP at a client site like from CD, do you guys just install all filesets
with the name cluster.*? The install guide lists all of the filesets which come with AIX, but deson't tell me what I should install exactly. There seems to be alot of unnecessary filesets on the media for just like a base HACMP install. Could you list the filesets you install?
2.) GPFS. This is from what I understand. You have a shared SAN disk with like an Oracle database, or something you are making highly available with HACMP. You have the vg which is on the disk imported, on both nodes, for fast disk takeover. Now, GPFS takes it a step forward, and allows you to not only have the disk imported in active-passive mode on both nodes, but allows you to mount that resource group's filesystems on both nodes simultaneously. GPFS coordinates the read/write activity to the disk by both nodes for consistency.
3.) I'm a little confused on the network interfaces. I know there is a boot interface, which I believe is also known as the base (Is that correct)? Some cluster configs I've been reading about have another boot, what's up with that? There is a persistent which I'm pretty clear on, and a service ip which I totally understand. The boot ip is kind of throwing me for a loop though. Could you explain that? What is the boot ip, and what is it used for? The only thing I could put together is that the boot ip is the ip which is on the interface before the HACMP cluster services daemons are started on node, but there has to be more to it's role. What is its role in the cluster? What is the state of that ip address(boot), when the cluster services daemons are started?
4.) Where does the heartbeat/keep alive packets travel through? What interface?
5.) Could you provide a real basic diagram of a typical HACMP cluster in AIX? I attempted to start the following text diagram. If you could fill in the rest, or correct any portion of it where I might be wrong, I'd appreciate it:
Two AIX nodes with the AIX bos installed locally on internal disks - rootvg..
There is a disk presented/zoned to the wwns of both nodes via the SAN. Both nodes see the same disk.
The HACMP software is installed locally on both nodes
Both nodes belong to a standby cluster I'll call "ora_aix_ha_clus1"
The two node names which are part of the cluster are named after their hostnames to keep things sane - aixoradb1, aixoradb2.
The Oracle database is installed on the SAN disk, oracle home, and the Oracle database files, dbfs, control files, redo logs, archive logs, etc., reside on the shared disk on the SAN.
We have three ip addresses on both nodes:
Boot ip which is there when the system boots, and before cluster services is started.
Persistent ip which is always there regardless of the cluster services state, for admin management of the node.
Standby ip which belongs to a resource group to be moved from aixoradb1(home node), to aixoradb2 in the event of a failover.
The shared vg will be imported to both nodes. It will be varied on to aixoradb1 in active mode with filesystems mounted, and in passive mode on aixoradb2 with no filesystems mounted.
In the event of a failover the following will happen:
The vg currently in passive mode on aixoradb2 will be varied on to active mode.
The filesystems will all be mounted making the Oracle files visible to aixoradb2.
The application server startup script will be started which will re-start the Oracle database on the shared disk on aixoradb2 which will perform instance recovery, and bring that Oracle database up again.
The service ip address via alias replacement, since that seems to be recommended over replacement, will be configured onto an interface on aixoradb2.
Now the Oracle client applications who were previously connected to the database via aixoradb1, will be knocked off of their connection briefly, but once the resource group is completely moved to aixoradb1,
then when the clients reconnect their application again it will reconnect to the database again. It will be transparent to them however that the ip address actually moved, and they are talking to another physical
server which is hosting the same database.
This was obviously a very simple scenario. I just wanted to ensure that I understood it from a very high level.
Please answer, and confirm when you get a moment.
Thanks in advance.
sandeep kumar- AIX/TSM/HACMP Administrator
