Explanation/Reference:
Explanation:
In Oracle RAC environments, RDBMS gathers global cache work load statistics which are reported in STATSPACK, AWRs and GRID CONTROL. Global cache lost blocks statistics ("gc cr block lost" and/or
"gc current block lost") for each node in the cluster as well as aggregate statistics for the cluster represent a problem or inefficiencies in packet processing for the interconnect traffic. These statistics should be monitored and evaluated regularly to guarantee efficient interconnect Global Cache and Enqueue Service (GCS/GES) and cluster processing. Any block loss indicates a problem in network packet processing and should be investigated.
Symptoms:
Primary:
Secondary:
Changes
As explained above, Lost blocks are generally caused by unreliable Private network. This can be caused by a bad patch or faulty network configuration or hardware issue.
Cause
In most cases, gc block lost has been attributed to (a) A missing OS patch (b) Bad network card (c) Bad cable (d) Bad switch (e) One of the network settings.
Oracle Metalink "gc block lost diagnostics [ID 563566.1]"