Instance crashed with ORA-481

Bug 11875294  LMS gets stuck during DRM, Instance crashed with ORA-481

 This note gives a brief overview of bug 11875294. 
 The content was last updated on: 20-OCT-2011
 Click here for details of each of the sections below.

Affects:

Product (Component)	Oracle Server (Rdbms)
Range of versions believed to be affected	Versions BELOW 12.1
Versions confirmed as being affected	11.2.0.2
Platforms affected	Generic (all / most platforms affected)

Fixed:

This issue is fixed in

12.1 (Future Release) 11.2.0.3

Symptoms:	Related To:
Instance May Crash ORA-481	RAC (Real Application Clusters) / OPS _gc_read_mostly_locking

Description

Rediscovery Notes:
 LMS processes can get stalled during the DRM reconfiguration due to 
 LE shortage, and this can lead to DRM timeout and instance crashes.
 eg:
  2011-08-25 10:03:45.232033 :Start affinity expansion for pkey 81885.0
  2011-08-25 10:03:46.698163 : Expand failed: pkey 81885.0, 1885 shadows traversed, 853 replayed 1 retries
 
The fix for this bug takes care of the problem by closing  
anti-locks first and also non-remastered locks to free up more LEs.
 
Workaround
 Disable read-mostly locking by setting:
  _gc_read_mostly_locking=FALSE.
 
Note:
 It is unlikely that interim patches will be produced for this 
 issue. Hence please use the workaround above or move to 11.2.0.3 
 (or higher) where the issue is fixed.