Preparing the Continental Cluster for Data Replication

Ensure that the XP Series disk arrays are correctly cabled to each host system in the two clusters that will run packages whose data reside on the arrays.

Each XP Series disk array must be configured with redundant CA links, each of which is connected to a different LCP or RCP card. To prevent a single point of failure (SPOF), there must be at least two physical boards in each XP for the CA links. Each board usually has multiple ports. However, a redundant CA link must be connected to a port on a different physical board from the board that has the primary CA link. When using bi-directional configurations, where data center A backs up data center B and data center B backs up data center A, you must have at least four CA links, two in each direction. Four CA links are also required in uni-directional configurations in which you want to allow failback.

Install the Raid Manager XP software on each host system that has data residing on the XP disk arrays.

Edit the /etc/services file, adding an entry for the Raid Manager instance to be used with ContinentalClusters.

The format of the entry is:

horcm<instance-number> <port-number>/udp

For example:

horcm0 11000/udp #Raid Manager instance 0

For more detail, see the /opt/cmcluster/toolkit/SGCA/Samples-CC/services.example file.

Use the ioscan command to determine what devices on the XP disk array have been configured as command devices. The device-specific information in the rightmost column of the ioscan output will have the suffix -CM for these devices; e.g., OPEN-3-CM.

If there are no configured command devices on the disk array, you must create two before proceeding. Each command device must have alternate links (PVLinks). The first command device is the primary command device. The second command device is a redundant command device and is used only upon failure of the primary command device. The command devices must be mapped to the various host interfaces by using the SVP (disk array console) or a remote console.

Copy the default Raid Manager configuration file to an instance-specific name. Example:

# cp /etc/horcm.conf /etc/horcm0.conf

Create a minimum Raid Manager configuration file by editing the following fields in the file created in the previous step:

If the Raid Manager protection facility is enabled, export the HORCPERM environment variable to the HORCM permission file:

# export HORCMPERM=/etc/horcmperm0.conf

If the Raid Manager protection facility is not used or disabled, export the HORCPERM environment variable as follows:

# export HORCMPERM=MGRNOINST

Start the Raid Manager instance by using the command horcmstart.sh <instance-#>. For example:

# horcmstart.sh 0

Export the environment variable that specifies the Raid Manager instance to be used by the Raid Manager commands. For example, with the POSIX shell type:

# export HORCMINST=0

Now, you can use Raid Manager commands to get further information from the disk arrays.

To verify the software revision of the Raid Manager and the firmware revision of the XP disk array, use the command:

# raidqry -l

	NOTE: Ensure that you have the minimum requirement level for the XP and the Raid Manager software and firmware listed in the ContinentalClusters release notes.

To get a list of the available devices on the disk arrays, use the command

# raidscan

This command must be invoked separately for each host interface connection to the disk array. For example, if there are two Fibre Channel host adapters, you might use the commands:

# raidscan -p CL1-A

# raidscan -p CL1-B

	NOTE: There must also be alternate links for each device, and these alternate links must be on different busses inside the XP disk array. These alternate links, for example, may be CL2-E and CL2-F.

Unless the devices have been previously paired either on this or another host, the devices will show up as SMPL (simplex). Paired devices will show up as PVOL (primary volume) or SVOL (secondary volume).

Determine which devices will be used by the application package. Define a device group that contains all of these devices. It is recommended that you use a name that is easily associated with the package. For example, a device group name of "db-payroll" is easily associated with the database for the payroll application. A device group name of "group1" would be more difficult to easily relate to an application.

Edit the Raid Manager configuration file (horcm0.conf in the above example) to include the devices and device group used by the application package. Only one device group may be specified for all of the devices that belong to a single application package. These devices are specified in the field HORCM_DEV.

Also complete the HORCM_INST field, supplying the names of only those hosts that are attached to the XP disk array that is remote from the disk array directly attached to this host. For example, with the continental cluster shown in Figure 6-1 “Continental Cluster” (node 1 and node 2 in the primary cluster and nodes 3 and 4 in the recovery cluster), you would specify only nodes 3 and 4 in the HORCM_INST field in a file you are creating on node 1 on the primary cluster. Node 1 would have previously been specified in the HORCM_MON field.

Figure 6-1 Continental Cluster

See file /opt/cmcluster/toolkit/SGCA/Samples-CC/horcm0.conf.<sys-name> for an example.

Restart the Raid Manager instance so that the new information in the configuration file is read. Use the commands:

# horcmshutdown.sh <instance-#>

# horcmstart.sh <instance-#>

Repeat these steps on each host that will run this particular application package. If a host may run more than one application package, you must incorporate device group and host information for each of these packages. Note that the Raid Manager configuration file must be different for each host, especially for the HORC_MON and HORC_INST fields.

If not previously done, you can create the paired volumes by using the command:

# paircreate -g <devgroup> -f <fencelevel> -vl -c15

This command must be issued before you create volume groups.

	WARNING! Paired devices must be of compatible sizes and types.

When using the paircreate command to create PVOL/SVOL CA pairs, specify the -c 15 switch to ensure the fastest data copy from PVOL to SVOL.