RAC有两个节点，节点二启动失败，手动启动报错：
[root@PTFDB2 ~]# cd /u01/app/11.2.0/grid
[root@PTFDB2 grid]# ./crsctl start crs
CRS-4640: Oracle High Availability Services is already active
CRS-4000: Command Start failed, or completed with errors.

在节点一查看RAC状态
[grid@PTFDB1 ~]$ crs_stat -t
Name           Type           Target    State     Host        
------------------------------------------------------------
ora.DATA.dg    ora....up.type ONLINE    ONLINE    ptfdb1      
ora.FRA.dg     ora....up.type ONLINE    ONLINE    ptfdb1      
ora....ER.lsnr ora....er.type ONLINE    ONLINE    ptfdb1      
ora....N1.lsnr ora....er.type ONLINE    ONLINE    ptfdb1      
ora.OCR.dg     ora....up.type ONLINE    ONLINE    ptfdb1      
ora.REDO1.dg   ora....up.type ONLINE    ONLINE    ptfdb1      
ora.REDO2.dg   ora....up.type ONLINE    ONLINE    ptfdb1      
ora.asm        ora.asm.type   ONLINE    ONLINE    ptfdb1      
ora.cvu        ora.cvu.type   ONLINE    ONLINE    ptfdb1      
ora.gsd        ora.gsd.type   OFFLINE   OFFLINE               
ora....network ora....rk.type ONLINE    ONLINE    ptfdb1      
ora.oc4j       ora.oc4j.type  ONLINE    ONLINE    ptfdb1      
ora.ons        ora.ons.type   ONLINE    ONLINE    ptfdb1      
ora.ptfdb.db   ora....se.type ONLINE    ONLINE    ptfdb1      
ora....SM1.asm application    ONLINE    ONLINE    ptfdb1      
ora....B1.lsnr application    ONLINE    ONLINE    ptfdb1      
ora.ptfdb1.gsd application    OFFLINE   OFFLINE               
ora.ptfdb1.ons application    ONLINE    ONLINE    ptfdb1      
ora.ptfdb1.vip ora....t1.type ONLINE    ONLINE    ptfdb1      
ora.ptfdb2.vip ora....t1.type ONLINE    ONLINE    ptfdb1      
ora....ry.acfs ora....fs.type ONLINE    ONLINE    ptfdb1      
ora.scan1.vip  ora....ip.type ONLINE    ONLINE    ptfdb1

之前grid实例的MEMORY_TARGET被人为修改成较大的值，导致ASM实例在启动时报错，登录节点一的ASM实例，修改内存参数：
[grid@PTFDB1 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.3.0 Production on Wed Jun 15 15:42:32 2016

Copyright (c) 1982, 2011, Oracle.  All rights reserved.

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options

SQL> show parameter memory

NAME     TYPE VALUE
------------------------------------ ----------- ------------------------------
memory_max_target     big integer 512M
memory_target     big integer 512M
SQL> show parameter sga

NAME     TYPE VALUE
------------------------------------ ----------- ------------------------------
lock_sga     boolean FALSE
sga_max_size     big integer 512M
sga_target     big integer 0
SQL> show parameter sga

SQL> show parameter spfile

NAME     TYPE VALUE
------------------------------------ ----------- ------------------------------
spfile     string +OCR/ptfdb-cluster/asmparamete
rfile/registry.253.841152655
SQL> alter system set memory_target=512M scope=spfile;

System altered.

SQL> alter system set memory_max_target=512M scope=spfile;

System altered.

SQL> alter system set sga_max_size=512M scope=spfile;

System altered.

SQL> alter system set sga_target=512M scope=spfile;

System altered.

登录节点二的ROOT用户，手动杀掉已经启动的RAC进程
[root@PTFDB2 ~]# ps -fea | grep ohasd.bin | grep -v grep
root      8701     1  0 Jun14 ?        00:01:05 /u01/app/11.2.0/grid/bin/ohasd.bin reboot
[root@PTFDB2 ~]# ps -fea | grep gipcd.bin | grep -v grep 
grid      8985     1  0 Jun14 ?        00:01:30 /u01/app/11.2.0/grid/bin/gipcd.bin
[root@PTFDB2 ~]# ps -fea | grep mdnsd.bin | grep -v grep 
grid      8930     1  0 Jun14 ?        00:00:03 /u01/app/11.2.0/grid/bin/mdnsd.bin
[root@PTFDB2 ~]# ps -fea | grep gpnpd.bin | grep -v grep 
grid      8946     1  0 Jun14 ?        00:00:33 /u01/app/11.2.0/grid/bin/gpnpd.bin
[root@PTFDB2 ~]# ps -fea | grep evmd.bin | grep -v grep 
grid      9237     1  0 Jun14 ?        00:02:30 /u01/app/11.2.0/grid/bin/evmd.bin
[root@PTFDB2 ~]# ps -fea | grep crsd.bin | grep -v grep
[root@PTFDB2 ~]# kill -9 8701 8985 8930 8946 9237

启动CRS
[root@PTFDB2 bin]# ./crsctl start crs
CRS-4123: Oracle High Availability Services has been started
[grid@PTFDB2 ~]$ crs_stat -t
Name           Type           Target    State     Host        
------------------------------------------------------------
ora.DATA.dg    ora....up.type ONLINE    ONLINE    ptfdb1      
ora.FRA.dg     ora....up.type ONLINE    ONLINE    ptfdb1      
ora....ER.lsnr ora....er.type ONLINE    ONLINE    ptfdb1      
ora....N1.lsnr ora....er.type ONLINE    ONLINE    ptfdb1      
ora.OCR.dg     ora....up.type ONLINE    ONLINE    ptfdb1      
ora.REDO1.dg   ora....up.type ONLINE    ONLINE    ptfdb1      
ora.REDO2.dg   ora....up.type ONLINE    ONLINE    ptfdb1      
ora.asm        ora.asm.type   ONLINE    ONLINE    ptfdb1      
ora.cvu        ora.cvu.type   ONLINE    ONLINE    ptfdb1      
ora.gsd        ora.gsd.type   OFFLINE   OFFLINE               
ora....network ora....rk.type ONLINE    ONLINE    ptfdb1      
ora.oc4j       ora.oc4j.type  ONLINE    ONLINE    ptfdb1      
ora.ons        ora.ons.type   ONLINE    ONLINE    ptfdb1      
ora.ptfdb.db   ora....se.type ONLINE    ONLINE    ptfdb1      
ora....SM1.asm application    ONLINE    ONLINE    ptfdb1      
ora....B1.lsnr application    ONLINE    ONLINE    ptfdb1      
ora.ptfdb1.gsd application    OFFLINE   OFFLINE               
ora.ptfdb1.ons application    ONLINE    ONLINE    ptfdb1      
ora.ptfdb1.vip ora....t1.type ONLINE    ONLINE    ptfdb1      
ora....SM2.asm application    ONLINE    ONLINE    ptfdb2      
ora....B2.lsnr application    ONLINE    ONLINE    ptfdb2      
ora.ptfdb2.gsd application    OFFLINE   OFFLINE               
ora.ptfdb2.ons application    ONLINE    ONLINE    ptfdb2      
ora.ptfdb2.vip ora....t1.type ONLINE    ONLINE    ptfdb2      
ora....ry.acfs ora....fs.type ONLINE    ONLINE    ptfdb1      
ora.scan1.vip  ora....ip.type ONLINE    ONLINE    ptfdb1

启动数据库，数据库恢复正常
SQL> startup