Hello,
vxglm is basically a module for lock management to have a consistent view of filesystem across all the nodes.
From SFRAC Install & config guide:
CFS uses a distributed locking mechanism called Global Lock Manager (GLM) to ensure all nodes have a consistent view of the file system. GLM
provides metadata and cache coherency across multiple nodes by coordinating access to file system metadata, such as inodes and free lists. The role of GLM is set on a per-file system basis to enable load balancing.
CFS involves a primary/secondary architecture. Though any node can initiate an operation to create, delete, or resize data, the GLM master node carries out the actual operation. After creating a file, the GLM master node grants locks for data coherency across nodes. For example, if a node tries to modify a row of a block in a file, it must obtain an exclusive lock to ensure other nodes that may have the same file cached have this cached copy invalidated.
SF Oracle RAC configurations minimize the use of GLM locking.
Oracle RAC accesses the file system through the ODM interface and handles its own locking; only Oracle (and not GLM) buffers data and coordinates write operations to files.
More details can be found in same guide...
vxglm depends on GAB & can't be started unless GAB is configured ..
Hope this helps..
Gaurav
