昨天处理了一个小case，后来发现不知道哪位亲爱的朋友修改了/etc/hosts文件，导致数据库趴下了，记录一下

[root@padb ~]# su - oracle<padb:padb:/home/oracle>$<padb:padb:/home/oracle>$ps -ef|grep ora_oracle 5874 5847 0 11:35 pts/3 00:00:00 grep ora_<padb:padb:/home/oracle>$lsnrctl statusLSNRCTL for Linux: Version 11.2.0.3.0 - Production on 12-JUL-2018 11:35:33Copyright (c) 1991, 2011, Oracle. All rights reserved.Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))###########监听卡在这里了####################<padb:padb:/home/oracle>$ps -ef|grep lsnroracle 5808 5757 0 11:34 pts/1 00:00:00 lsnrctl startoracle 5810 1 99 11:34 ? 00:01:36 /u01/app/oracle/product/11.2.0/dbhome_1/bin/tnslsnr LISTENER -inheritoracle 5877 5847 0 11:35 pts/3 00:00:00 grep lsnr##############进程在<padb:padb:/home/oracle>$kill -9 5810<padb:padb:/home/oracle>$ps -ef|grep lsnroracle 5879 5847 0 11:35 pts/3 00:00:00 grep lsnr##############kill 进程 <padb:padb:/home/oracle>$sqlplus / as sysdbaSQL*Plus: Release 11.2.0.3.0 Production on Thu Jul 12 11:35:56 2018Copyright (c) 1982, 2011, Oracle. All rights reserved.Connected.SQL> ###############很诡异的一个状态，竟然connected了##############查看日志<padb:padb:/home/oracle>$uptime 11:36:27 up 50 min, 4 users, load average: 0.42, 0.33, 0.47<padb:padb:/home/oracle>$adrciADRCI: Release 11.2.0.3.0 - Production on Thu Jul 12 11:36:35 2018Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.ADR base = "/u01/app/oracle"adrci> show alertChoose the alert log from the following homes to view:1: diag/clients/user_oracle/host_61728193_802: diag/rdbms/padb/padb3: diag/tnslsnr/localhost/listener4: diag/tnslsnr/padb/listenerQ: to quitPlease select option: 2Output the results to file: /tmp/alert_5886_14061_padb_1.ado2017-12-05 18:40:29.250000 +08:00Starting ORACLE instance (normal)****************** Large Pages Information *****************Total Shared Global Region in Large Pages = 0 KB (0%)Large Pages used by this instance: 0 (0 KB)Large Pages unused system wide = 0 (0 KB) (alloc incr 64 MB)Large Pages configured system wide = 0 (0 KB)Large Page size = 2048 KBRECOMMENDATION: Total Shared Global Region size is 24 GB. For optimal performance, prior to the next instance restart increase the number of unused Large Pages by atleast 12097 2048 KB Large Pages (24 GB) system wide to get 100% of the Shared Global Region allocated with Large pages***********************************************************LICENSE_MAX_SESSION = 0LICENSE_SESSIONS_WARNING = 0Shared memory segment for instance monitoring createdPicked latch-free SCN scheme 3Machine:x86_64VM name:VMWare Version: 6home_1/dbs/spfilepadb.oraSystem parameters with non-default values: processes = 500 sessions = 780 sga_target = 24192M control_files = "/u01/app/oracle/padb/control01.ctl" control_files = "/u01/app/oracle/padb/control02.ctl" db_block_size = 8192 compatible = "11.2.0.0.0" undo_tablespace = "UNDOTBS1" remote_login_passwordfile= "EXCLUSIVE" db_domain = "" dispatchers = "(PROTOCOL=TCP) (SERVICE=padbXDB)" audit_file_dest = "/u01/app/oracle/admin/padb/adump" audit_trail = "DB" db_name = "padb" open_cursors = 300 pga_aggregate_target = 8053M diagnostic_dest = "/u01/app/oracle"USER (ospid: 5117): terminating the instance due to error 119ORACLE_HOME = /u01/app/oracle/product/11.2.0/dbhome_1System name:LinuxNode name:padbRelease:2.6.32-573.el6.x86_64Version:#1 SMP Wed Jul 1 18:23:37 EDT 2015Machine:x86_64VM name:VMWare Version: 6Using parameter settings in server-side spfile /u01/app/oracle/product/11.2.0/dbbhome_1/dbs/spfilepadb.oraSystem parameters with non-default values: processes = 500 sessions = 780 sga_target = 24192M control_files = "/u01/app/oracle/padb/control01.ctl" control_files = "/u01/app/oracle/padb/control02.ctl" db_block_size = 8192 compatible = "11.2.0.0.0" undo_tablespace = "UNDOTBS1" remote_login_passwordfile= "EXCLUSIVE" db_domain = "" dispatchers = "(PROTOCOL=TCP) (SERVICE=padbXDB)" audit_file_dest = "/u01/app/oracle/admin/padb/adump" audit_trail = "DB" db_name = "padb" open_cursors = 300 pga_aggregate_target = 8053M diagnostic_dest = "/u01/app/oracle"USER (ospid: 5117): terminating the instance due to error 119 remote_login_passwordfile= "EXCLUSIVE" db_domain = "" dispatchers = "(PROTOCOL=TCP) (SERVICE=padbXDB)" audit_file_dest = "/u01/app/oracle/admin/padb/adump" audit_trail = "DB" db_name = "padb" open_cursors = 300 pga_aggregate_target = 8053M diagnostic_dest = "/u01/app/oracle"2018-07-12 09:45:28.043000 +08:00USER (ospid: 18388): terminating the instance due to error 119Instance terminated by USER, pid = 18388 ############实例异常终止了2018-07-12 09:47:53.701000 +08:00Starting ORACLE instance (normal)"/tmp/alert_5886_14061_padb_1.ado" 13117L, 632251C written<padb:padb:/home/oracle>$df -hFilesystem Size Used Avail Use% Mounted on/dev/mapper/VolGroup-lv_root 627G 512G 84G 86% /tmpfs 32G 72K 32G 1% /dev/shm/dev/sda1 477M 42M 410M 10% /boot<padb:padb:/home/oracle>$<padb:padb:/home/oracle>$sqlplus / as sysdbaSQL*Plus: Release 11.2.0.3.0 Production on Thu Jul 12 11:47:10 2018Copyright (c) 1982, 2011, Oracle. All rights reserved.Connected.SQL> startupORA-00119: invalid specification for system parameter LOCAL_LISTENERORA-00130: invalid listener address ‘(ADDRESS=(PROTOCOL=TCP)(HOST=padb)(PORT=1521))‘SQL> ##########第一意识ping了一下主机名<padb:padb:/u01/app/oracle/diag/rdbms/padb/padb/trace>$ping padbping: unknown host padb<padb:padb:/u01/app/oracle/diag/rdbms/padb/padb/trace>$ping padbping: unknown host padb<padb:padb:/u01/app/oracle/diag/rdbms/padb/padb/trace>$hostnamepadb<padb:padb:/u01/app/oracle/diag/rdbms/padb/padb/trace>$more /etc/hosts127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4::1 localhost localhost.localdomain localhost6 localhost6.localdomain6padb 10.18.0.84 ##到这里，只能无语了,外加18个点点点，这是啥啊！！！！<padb:padb:/u01/app/oracle/diag/rdbms/padb/padb/trace>$ping padbping: unknown host padb<padb:padb:/u01/app/oracle/diag/rdbms/padb/padb/trace>$exitlogout####修改host文件[root@padb ~]# vi /etc/hosts127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4::1 localhost localhost.localdomain localhost6 localhost6.localdomain610.18.0.84 padb "/etc/hosts" 3L, 175C written[root@padb ~]# [root@padb ~]# [root@padb ~]# ping padbPING padb (10.18.0.84) 56(84) bytes of data.64 bytes from padb (10.18.0.84): icmp_seq=1 ttl=64 time=0.029 ms64 bytes from padb (10.18.0.84): icmp_seq=2 ttl=64 time=0.021 ms^C--- padb ping statistics ---2 packets transmitted, 2 received, 0% packet loss, time 1804msrtt min/avg/max/mdev = 0.021/0.025/0.029/0.004 ms[root@padb ~]# Refer to the SQL*Plus User‘s Guide and Reference for more information.<padb:padb:/home/oracle>$sqlplus / as sysdbaSQL*Plus: Release 11.2.0.3.0 Production on Thu Jul 12 12:01:43 2018Copyright (c) 1982, 2011, Oracle. All rights reserved.Connected to an idle instance.SQL> startupORACLE instance started.Total System Global Area 2.5254E+10 bytesFixed Size 2240096 bytesVariable Size 3221225888 bytesDatabase Buffers 2.2012E+10 bytesRedo Buffers 18718720 bytesDatabase mounted.Database opened.SQL> exit