Using LVM with DataKeeper

LifeKeeper for Linux currently supports both the use of DataKeeper “above” LVM and LVM “above” DataKeeper. In a standard DataKeeper configuration, using DataKeeper above LVM is supported and DO NOT install the LifeKeeper LVM Recovery Kit. DataKeeper is the only recovery kit necessary. However, using the LVM above DataKeeper configuration, the LVM Recovery Kit is required.

SIOS recommends using DataKeeper above LVM; however, if the LVM above DataKeeper configuration is being used, a two-phase hierarchy creation process must be used. The DataKeeper devices (i.e. hierarchies) must be configured using the DataKeeper “Data Replication Resource” option prior to the creation of the LVM volume groups and logical volumes on the primary server. Once the desired volume groups and logical volumes have been created, the remainder of the hierarchy is created according to the configuration instructions for the recovery kit associated with the application to be protected. The resulting hierarchy will look something like the one shown in Figure 3 below.

*Note: For data consistency reasons, in an LVM over DataKeeper configuration, there must either be only one DataKeeper mirror or multiple synchronous mirrors.

Figure 3: Hierarchy with LVM above DataKeeper

A single terminal leaf resource should be created as a child of each of the DataKeeper resources. This will provide a single resource when taking the hierarchy out-of-service and will assure that during switchover operations the entire hierarchy is out-of-service before any resource is brought in-service on another node. See the man page for create_terminal_leaf(1M) for more details.

To create a terminal leaf for the hierarchy in Figure 3 run the following command:

$LKROOT/bin/create_terminal_leaf home/testlv