vradmin ibc command enables you to perform off-host processing operation in a single command.
The Primary RLINK that points to the Secondary host participating in the
ibc command must be in the connect state.
onfreeze script must exist on each Secondary host participating in the
Make sure each user-defined script to be used in the
ibc command exits with a status of 0 on successful completion and a status of nonzero on unsuccessful completion.
The user-defined scripts must have
execute permissions for
ibc executes scripts using root privileges. If the scripts can be modified by a non-privileged user, there is a potential security risk. To prevent this, ensure that you have the proper access privileges set on the scripts used with the
To perform an off-host processing task on one or more Secondary RVGs in an RDS
startrepcommand to start replication.
task_name is the name of the off-host processing task and is the same as the
task_name argument used in the
vradmin -g diskgroup
diskgroup represents the disk group that contains the RVG on the local host.
rvg_name is the name of the RVG on the local host and represents its RDS.
task_name is the name of the off-host processing task and is the same as the name of the directory created in step a.
sechost is the name of the Secondary host as displayed in the output of the
printrvg command. The argument
sechost is optional if the RDS contains only one Secondary. To perform the task on multiple Secondary hosts, specify a space-separated list with the name of each Secondary to be included. Use the
-all option to perform the task on all the Secondary hosts in the RDS.
Example-Creating a snapshot on the Secondary using the vradmin ibc command
This example shows how to create a snapshot of the data volumes on the Secondary
london using the
ibc command. The RVG
hr_rvg, which belongs to the disk group
hrdg, has been created on the Primary and Secondary. This example also assumes that Secondary data volumes have associated snapshot plexes. It uses the application name
onfreezescript in the
/etc/vx/vvr/ibc_scripts/dss_appdirectory on the Secondary host by including the following command to create the snapshot of the data volumes on the Secondary:
/usr/sbin/vxrvg -g hrdg snapshot hr_rvg
vradmin -g hrdg ibc hr_rvg dss_app london
ibc command executes the user-defined scripts:
prefreeze, quiesce, unquiesce, onfreeze, and postfreeze. Note that the
onfreeze script is mandatory and must be present on the Secondary. The scripts
postfreeze are optional. However, if you provide the
quiesce script, you must provide the
unquiesce script and vice versa. You must name the user-defined scripts
Note A user-defined script can either be a shell script or a binary.
Location of the scripts
The scripts must reside in the
task_name directory on the Primary and the Secondary host. Note that task_name is the name of the off-host processing task and is the same as the
task_name argument used in the
ibc command. For example, if the off-host processing task is Decision Support Systems (DSS), you can choose a task name of
dss; or if the off-host processing task is Backup, you can choose the task name of
In a shared disk group environment, the scripts must exist on each node in the Primary or Secondary cluster. That is, the
unquiesce scripts must exist on each node in the Primary cluster; the
postfreeze scripts must exist on each node in the Secondary cluster.
ibc command executes each script, it passes the following arguments to the script:
The following section describes how each script is used with the
Use this script on the Secondary to prepare for the tasks to be performed in the
onfreeze script while the replication to Secondary is frozen. For example, if you want to take a snapshot of the Secondary data volumes while the replication on the Secondary is frozen, the
prefreeze script can be used to add snapshot plexes to the Secondary data volumes to prepare for the
ibc command executes the
quiesce script on the Primary before it sends the IBC message to the Secondary. Use this script to quiesce the application running on the Primary RVG and to make the Primary data volumes consistent at the application level. The
ibc command injects an IBC message in a small amount of time, and hence the duration for which the application remains quiesced is small.
ibc command executes this script on the Primary after it sends the IBC message to the Secondary. Use this script to resume the application running on the Primary if the application was quiesced.
ibc command executes this script on the Secondary while replication on the Secondary is frozen after receiving the IBC message from the Primary. Use this script to perform the required off-host processing operation, for example, taking a snapshot of the Secondary data volumes.
ibc command executes this script on the Secondary after it executes the
onfreeze script and after the replication on the Secondary is unfrozen. For example, if a snapshot of the Secondary data volumes was taken in the
onfreeze script, this script can be used to reattach the snapshot volumes to the Secondary data volumes.
/etc/vx/vvr/ibc_scripts directory contains the following sample script directories
These sample scripts show how to use the user-defined scripts with the
ibc command. Refer to the README file provided in
/etc/vx/vvr/ibc_scripts directory for instructions on how to use the sample scripts to perform off-host processing tasks.
Note Sample scripts are provided for reference. Customize the sample scripts to suit your requirements.