As with the virtual machine setup, there are
just two critical modifications you need to make during the
operating system install. There are also a host of additional steps
necessary to support ocfs2 and other RAC prerequisites, which will
be reviewed now.
The first change during the OS install is to
create a second disk device (/dev/sdb) shown below in Figure 4 based
off your second VMware hard disk device, which is Hard Disk 2 from
the prior section. You do not need to create a file system on it yet
that will be accomplished later. You only need the OS to recognize
and know about it for now.
Figure 4:
Creating a Second Disk Device
The second change during the OS install is to
configure a second Ethernet network device, eth1, for your Oracle
private network or interconnect (Figure 5). Although the assigned IP
addresses may look very similar, note that one is on subnet 100 and
the other subnet 200. This is a very easy item to miss which can
have drastic ramifications, such as the RAC cluster services failing
to start or otherwise communicate. So take your time on this screen
and make sure these settings and your hosts file entries match.
Figure 5: Configuring Second Ethernet Network Device
Once the operating system install is complete
and you have done all the other operating system steps from the
prior chapter, there are still a few remaining issues to address
before moving on to the Oracle software install step.
First, you need to install the Oracle Cluster
File System Linux kernel packages that match your Linux kernel
version. So issue the uname r command as shown below to verify
your Linux kernel version, then merely obtain and install those
ocfs2 packages (shown on next page, Figure 6). Note that you must be
running as the root user to install packages.
Figure 6:
Verifying Linux Kernel Version
Second, (Figure 7) you need to run the
ocfs2console command, GUI, to initiate the cluster stack services
and to configure the cluster node.
Figure 7:
Cluster Stack Services Screen
Note that the ocfs2console directs you to run
the /etc/init.d/o2cd enable command to make sure that these cluster
services autostart on reboot. This is a critical step that is
sometimes easy to skip over with devastating results, i.e. your
cluster file system will not be accessible after reboot since the
necessary prerequisite cluster services wont be running. So please
do not skip this step.
Next, choose the Main Menu -> Cluster ->
Configure Nodes options to launch the screen shown on the following
page (Figure 8). Here you need to add your network alias and IP
address. You can permit the port to default. You are now done using
the ocfs2console utility.
Figure 8:
Adding Network Alias and IP Address
You have just three more steps to go to complete
your operating system level installation and configuration:
-
Configure the cluster services (optional step)
-
Format the cluster file system on /dev/sdb
-
Mount and/or auto-mount the ocfs2 file system
This first step is optional. However, I show it
since, for some real-world scenarios, this step may be critical
(such as in the next chapter). You merely take the ocfs2 file system
offline and unload its packages, then run its configuration script.
While it asks several questions, including one about the autostart
on reboot, its the heartbeat question that requires special
attention. It is not uncommon on lower capacity systems or systems
with inherent time lags (e.g. NAS or iSCSI) to require adjusting the
heartbeat threshold higher. For such occasions it is often quite
advisable to choose a value of 60 or higher. The default of 31 or
lower may often result in nodes appearing to sporadically hang.
Figure 9: Screen Showing Creating an ocfs2
File System
The second step is pretty straight forward - you
just need to create an ocfs2 file system on your device (e.g. /dev/sdb)
that you allocated during the operating system install for your
shared disk storage space required by Oracle RAC (Figure 9). You
then run the mkfs.ocfs command as shown below in Figure 10. As you
can see, I have chosen a block size of 4K, a cluster size of 32K,
and volume label of oracrsfiles. The block size may seem a bit
small by todays standards, but trust me for now and go with 4K. I
will explain why in Chapter 9 where I will cover some more advanced
tuning issues, especially as they relate to Oracle on virtual
machines.
Figure 10:
Screen Showing Block Size
Finally, you need to create your ocfs2 file
system mount point, change the owner to Oracle, set appropriate
permissions, and mount your new ocfs2 file system to verify that you
did everything correctly as shown on the next page in Figure 11.
Figure 11: Resolution of Proper Setup
If that all works as expected, then you need to
add an entry to your /etc/fstab file to make sure that the new ocfs2
file system is auto mounted on boot. You are now done with your
operating system level steps on to the Oracle software.
This is an excerpt from
Oracle on VMWare:
Expert tips for database virtualization
by Rampant TechPress.
and include the URL for the page.
