Storage capacity for the Oracle database must be provided
in the form of logical volumes located in shared volume groups.
The Oracle software requires an Oracle control file, several log
files for each Oracle instance, and files for the database itself.
For all these files, OPS uses HP-UX raw logical volumes, which are located in volume groups that are shared between
the nodes in the cluster. High availability is achieved by using high
availability disk arrays in RAID modes. The logical units of storage on
the arrays are accessed from each node through multiple physical volume
links (PV links, also known as alternate links), which provide redundant
paths to each unit of storage.
The following paragraphs show how to plan appropriate volume
groups, PV links, and logical volumes for your OPS demo database,
which is created by the Oracle installer software. If you do not wish to install the demo
database, use the same worksheets to define an appropriate set of
volume groups, physical volume groups, and logical volumes for your development
or production system.
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 | NOTE: If you are planning to run packages, you will need to
plan a volume group infrastructure for those volume groups that
will be used by packages. These volume groups must be separate from
volume groups that contain the OPS files. The basic methodology
for planning volume groups for packages is the same as for shared
volumes, but there are a few differences to note. Please see the
section “Package Configuration Planning” for details. |
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Planning Volume Groups |
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You should plan the number of OPS volume groups based on the availability
of disk resources and on your desire to subdivide your disk resources
for ease of maintenance or for other reasons. Although most of the
examples shown in this section use a single volume group, /dev/vg_ops,
you may wish to create more than one volume group. For example,
you may want to use one volume group per tablespace.
The default number of volume groups allowed is 10. If your
planned configuration will exceed this number, you need to change
the MAX_VGS parameter in the /stand/system file. For the changed
parameter to take effect, you need to re-build the kernel and reboot
the system. See the Managing Systems and Workgroups (B2355-90157) manual
for information on changing kernel parameters.
Planning Physical Volumes and PV Links |
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In order to create a volume group, you must identify the physical volumes
that will hold its data. To do this, examine the list of disks in
the output of the ioscan -fnC disk command (attached to the hardware worksheet).
Assuming you have a disk array attached to each node with two different
busses, identify which LUNs to be used for OPS are connected to
which different I/O bus. Assign all the disks from one bus to one
set of PV links, and assign all the disks from the other bus to
a second set of PV links. Do this for each node.
Planning Logical Volumes |
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A single volume group can hold up to 255 logical volumes,
and the largest logical volume that can be employed as a raw file
for OPS data is 4 GB. Thus, if your data is larger than 4 GB, you must use more than one logical volume. However, you may use as many as 255 logical volumes per volume group,
even when the total size of your data is much less than 4 GB. For
the OPS configuration, define enough logical volumes in appropriate
sizes for the data and logs you need.
Physical Volumes and PV Links Worksheet |
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Fill out the OPS Physical Volume worksheet for each node to
assist in adding the correct physical volumes to particular volume
groups in the vgcreate command. Figure 4-3 “OPS Physical Volume Worksheet” is a sample
worksheet filled out. Refer to the appendix, "Appendix E “Blank Planning Worksheets ”" for samples of blank worksheets. Make as
many copies as you need. Fill out the worksheet and keep it for
future reference.
Logical Volume Planning Worksheet |
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Fill out the Logical Volume worksheet to provide logical volume
names for OPS logical volumes that you will create with the lvcreate command. The Oracle DBA and the HP-UX system administrator
should prepare this worksheet together. Create entries for shared
volumes only. For each logical volume, enter the full pathname of
the raw logical volume device file. Be sure to include the desired
size in MB. Figure 4-4 “Logical Volume Worksheet” is a sample worksheet filled
out. Refer to the appendix, "Appendix E “Blank Planning Worksheets ”" for
samples of blank worksheets. Make as many copies as you need. Fill
out the worksheet and keep it for future reference.
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