Geographic Logical Volume Manager (GLVM)
The Geographic Logical Volume Manager (GLVM) provides a software-based mirroring method in GLVM for PowerHA® SystemMirror® Enterprise Edition that is used for mirroring your data in real-time over unlimited geographic distance.
The main function of the GLVM is mirroring of any data destined for nodes at a local site (the production site) across an IP-based network to nodes at a remote site (the backup site). A total failure (such as a CPU, disk, network, or power failure) of the node at the local site does not cause the loss of data on the node at the remote site.
The GLVM mirroring:
- Does not depend on the type of database and file system. There is no modification required of applications that use GLVM mirroring capabilities.
- Performs the data mirroring over standard TCP/IP networks without having a dependency on the specific data that is being mirrored.
- Is less expensive than hardware-based mirroring solutions and does not have distance limitations.
- Uses the mirroring function of the AIX® LVM and operates as a layer under the LVM.
With the AIX LVM and GLVM for PowerHA SystemMirror Enterprise Edition, you can create, change, and verify geographic mirror copies of your logical volumes. The mirror copies that you create must:
- Reside on different sites.
- Have the Super Strict inter-disk allocation policy for the logical volumes. This forces each complete copy of the logical volume to reside on separate sets of physical volumes and remote physical volumes (RPVs).
- Not be part of the root volume group.
The following figure illustrates the GLVM for PowerHA SystemMirror Enterprise Edition mirroring function:
The Geographic LVM includes:
- The remote physical volume (RPV) device driver.
- You can use the SMIT interface to configure RPVs for a volume group that you plan to replicate remotely. You can also use the SMIT interface to change and verify mirror copies for logical volumes and volume groups.
The GLVM also uses the AIX LVM mirroring capabilities.