OpenVMS Cluster Systems - OpenVMS Systems - HP

Building Large OpenVMS Cluster Systems
9.1 Setting Up the Cluster
To set up a new, large OpenVMS Cluster, follow these steps:
Step Task
1 Configure boot and disk servers using the CLUSTER_CONFIG_LAN.COM or the CLUSTER_
CONFIG.COM command procedure (described in Chapter 8).
2 Install all layered products and site-specific applications required for the OpenVMS Cluster
environment, or as many as possible.
3 Prepare the cluster startup procedures so that they are as close as possible to those that will
be used in the final OpenVMS Cluster environment.
4 Add a small number of satellites (perhaps two or three) using the cluster configuration
command procedure.
5 Reboot the cluster to verify that the startup procedures work as expected.
6 After you have verified that startup procedures work, run UETP_AUTOGEN.COM on
every computer’s local batch queue to reboot the cluster again and to set initial production
environment values. When the cluster has rebooted, all computers should have reasonable
parameter settings. However, check the settings to be sure.
7 Add additional satellites to double their number. Then rerun UETP_AUTOGEN on
each computer’s local batch queue to reboot the cluster, and set values appropriately to
accommodate the newly added satellites.
8 Repeat the previous step until all satellites have been added.
9 When all satellites have been added, run UETP_AUTOGEN a final time on each computer’s
local batch queue to reboot the cluster and to set new values for the production environment.
For best performance, do not run UETP_AUTOGEN on every computer
simultaneously, because the procedure simulates a user load that is probably
more demanding than that for the final production environment. A better method
is to run UETP_AUTOGEN on several satellites (those with the least recently
adjusted parameters) while adding new computers. This technique increases
efficiency because little is gained when a satellite reruns AUTOGEN shortly after
joining the cluster.
For example, if the entire cluster is rebooted after 30 satellites have been added,
few adjustments are made to system parameter values for the 28th satellite
added, because only two satellites have joined the cluster since that satellite ran
UETP_AUTOGEN as part of its initial configuration.
9.2 General Booting Considerations
Two general booting considerations, concurrent booting and minimizing boot time,
are described in this section.
9.2.1 Concurrent Booting
One of the rare times when all OpenVMS Cluster computers are simultaneously
active is during a cluster reboot—for example, after a power failure. All satellites
are waiting to reload the operating system, and as soon as a boot server is
available, they begin to boot in parallel. This booting activity places a significant
I/O load on the system disk or disks, interconnects, and boot servers.
For example, Table 9–1 shows a VAX system disk’s I/O activity and elapsed
time until login for a single satellite with minimal startup procedures when the
satellite is the only one booting. Table 9–2 shows system disk I/O activity and
time elapsed between boot server response and login for various numbers of
satellites booting from a single system disk. The disk in these examples has a
capacity of 40 I/O operations per second.
9–2 Building Large OpenVMS Cluster Systems