Oracle 11g GridInfra ocr backup files cleaning/rotating problem

Sometimes Oracle automatic ocr backup cleaning is not working and because of this your $ORA_CRS_HOME/cdata/<cluster_name>  directory is filled by .ocr backup files.

Cause of this problem is regular backup files ownership. Check following files:
---
-rw-r--r-- 1 oracle root 6557696 Jun 6 18:07 week.ocr 
-rw-r--r-- 1 oracle root 6569984 Jun 13 18:07 week_.ocr
-rw-r--r-- 1 oracle root 6569984 Jun 16 18:07 day.ocr
-rw-r--r-- 1 oracle root 6569984 Jun 17 18:07 day_.ocr
-rw-r--r-- 1 oracle root 6569984 Jun 18 06:07 backup02.ocr
-rw-r--r-- 1 oracle root 6569984 Jun 18 10:07 backup01.ocr
-rw-r--r-- 1 oracle root 6569984 Jun 18 14:07 backup00.ocr
---

These files ownership should be root:root

After you change ownership the new backup files are rotating correctly.
And then you can safely delete older files (which are starting with generic numbers). But don't delete those regular backup files  (week*, day*, backup*) they are used for rotating ocr backups.

There is also MOS document about this problem:

OCR Backup Filling Up $ORA_CRS_HOME/CDATA/<CLUSTER_NAME> Directory [ID 741271.1]