Create AWR report by sqlplus

set heading off;
set feedback off;
set linesize 1500;

select snap_id,dbid,begin_interval_time,end_interval_time from DBA_HIST_SNAPSHOT
order by 1;

replace your snap_id and dbid wtih following sql:

spool awr.html
select output from
table(dbms_workload_repository.awr_report_html(dbid,1,,));
spool off

sqlplus ORA-01031: insufficient privileges

You want to connect intance to start.(oracle 11g)

but there is an error.

like

[oracle@oratest01 ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.2.0 Production on Tue Jun 23 02:00:05 2009

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

ERROR:
ORA-01031: insufficient privileges

1-Check groups in linux.(if dba group doesn't exist firstly create it)

more /etc/group
.
....

oinstall:x:500:
dba:x:501:oracle


2-Check your oracle user groups

more /etc/passwd
.
....
oracle:x:500:500::/home/oracle:/bin/bash



[root@oratest01 ~]# id oracle
uid=500(oracle) gid=500(oinstall) groups=500(oinstall),501(dba)