[20160712]ASM ab_+ASM.dat.txt

[20160712]ASM ab_+ASM.dat.txt

--如果你使用asm，在dbs目錄下$ORACLE_HOME/dbs目錄下存在ab_+ASM.dat的檔案。
--11GR2在grid的使用者。

$ strings ab_+ASM.dat
GREP_COLOR=01;32
HOSTNAME=xxxxxdg2
TERM=linux
SHELL=/bin/bash
HISTSIZE=2000
KDE_NO_IPV6=1
TMPDIR=/tmp
NLS_LANG=AMERICAN_AMERICA.ZHS16GBK
QTDIR=/usr/lib64/qt-3.3
QTINC=/usr/lib64/qt-3.3/include
USER=oracle
HISTFILESIZE=2000
LS_COLORS=no=00:fi=00:di=01;34:ln=01;36:pi=40;33:so=01;35:bd=40;33;01:cd=40;33;01:or=01;05;37;41:mi=01;05;37;41:ex=01;32:*.cmd=01;32:*.exe=01;32:*.com=01;32:*.btm=01;32:*.bat=01;32:*.sh=01;32:*.csh=01;32:*.tar=01;31:*.tgz=01;31:*.arj=01;31:*.taz=01;31:*.lzh=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.gz=01;31:*.bz2=01;31:*.bz=01;31:*.tz=01;31:*.rpm=01;31:*.cpio=01;31:*.jpg=01;35:*.gif=01;35:*.bmp=01;35:*.xbm=01;35:*.xpm=01;35:*.png=01;35:*.tif=01;35:
LD_LIBRARY_PATH=/u01/app/oracle/product/10.2.0/rac_db/lib:/u01/app/oracle/product/10.2.0/rac_db/oracm/lib:/lib:/usr/lib:/usr/local/lib:/lib64:/usr/lib64:/usr/local/lib64
ORACLE_SID=+ASM
ON=/u01/app/oracle/product/10.2.0/rac_db/network/admin
OH=/u01/app/oracle/product/10.2.0/rac_db
ORACLE_HOSTNAME=xxxxxdg2
ORACLE_BASE=/u01/app/oracle
KDEDIR=/usr
OD=/u01/app/oracle/product/10.2.0/rac_db/dbs
PATH=
MAIL=/var/spool/mail/oracle
NXDIR=/usr/NX
OB=/u01/app/oracle
PWD=/home/oracle
INPUTRC=/etc/inputrc
NLS_TIMESTAMP_TZ_FORMAT=YYYY-MM-DD HH24:MI:SS.FF
KDE_IS_PRELINKED=1
LANG=en_US
OBDUMP=/u01/app/oracle/admin/xxxxxdg2/bdump
ORACLE_TERM=linux
OASMDUMP=/u01/app/oracle/admin/+ASM/bdump
SSH_ASKPASS=/usr/libexec/openssh/gnome-ssh-askpass
HOME=/home/oracle
SHLVL=2
GREP_OPTIONS=--color=auto
LOGNAME=oracle
TMP=/tmp
CVS_RSH=ssh
QTLIB=/usr/lib64/qt-3.3/lib
CLASSPATH=/u01/app/oracle/product/10.2.0/rac_db/JRE:/u01/app/oracle/product/10.2.0/rac_db/jlib:/u01/app/oracle/product/10.2.0/rac_db/rdbms/jlib
LESSOPEN=|/usr/bin/lesspipe.sh %s
ORACLE_HOME=/u01/app/oracle/product/10.2.0/rac_db
G_BROKEN_FILENAMES=1
HISTTIMEFORMAT=%F %T =
NLS_DATE_FORMAT=YYYY-MM-DD HH24:MI:SS
_=/u01/app/oracle/product/10.2.0/rac_db/bin/sqlplus
ORA_NET2_DESC=8,11
ORACLE_SPAWNED_PROCESS=1
SC=8,11
ORACLE_SPAWNED_PROCESS=1

--很明顯儲存一些環境。我改動1個引數
HISTSIZE=2001

-- 再重新登入看看：

$ strings ab_+ASM.dat |grep -i histsize
HISTSIZE=2000

--//並不會因此改變，也許要重啟asm例項。現在我無法重啟，留待以後觀察。

$ stat ab_+ASM.dat
  File: `ab_+ASM.dat'
  Size: 1981            Blocks: 8          IO Block: 4096   regular file
Device: 803h/2051d      Inode: 217219075   Links: 1
Access: (0660/-rw-rw----)  Uid: (  500/  oracle)   Gid: (  501/oinstall)
Access: 2016-07-12 08:18:47.000000000 +0800
Modify: 2014-09-21 04:24:05.000000000 +0800
Change: 2014-09-21 04:24:05.000000000 +0800

SYS@xxxxx> select STARTUP_TIME from v$instance;

STARTUP_TIME
-------------------
2014-09-21 04:24:24

--從時間看，這裡可以看出應該是啟動的時候會建立或者修改這個檔案。
--找到一個連結：

ab_+ASM.dat : This file generated when asm instance startup. this file is used by the RDBMS instance to determine the
appropriate enviornment information whenever the RDBMS instance connects to the asm instance. If this file is removed,
RDBMS instance can not able to connect to ASM。

--裡面測試還說明了如果mv了檔案，asm例項無法啟動，建立表空間失敗。我沒有測試環境，放棄測試。

SQL> startup
ORA-01078: failure in processing system parameters
ORA-01565: error in identifying file '+DATA/asmoracle/spfileasmoracle.ora'
ORA-17503: ksfdopn:2 Failed to open file +DATA/asmoracle/spfileasmoracle.ora
ORA-27300: OS system dependent operation:open failed with status: 2
ORA-27301: OS failure message: No such file or directory
ORA-27302: failure occurred at: sskgmsmr_7

SQL> create tablespace testtbs datafile '+DATA' size 1m;
create tablespace testtbs datafile '+DATA' size 1m
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 4644
Session ID: 1 Serial number: 17

--我僅僅測試建立表空間的情況：
$ mv ab_+ASM.dat ab_+ASM.dat_new

SYS@xxxxx> select * from v$version;
BANNER
----------------------------------------------------------------
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bi
PL/SQL Release 10.2.0.4.0 - Production
CORE    10.2.0.4.0      Production
TNS for Linux: Version 10.2.0.4.0 - Production
NLSRTL Version 10.2.0.4.0 - Production

SYS@xxxxx> create tablespace testtbs datafile '+g0' size 1m;
create tablespace testtbs datafile '+g0' size 1m
*
ERROR at line 1:
ORA-01119: error in creating database file '+g0'
ORA-17502: ksfdcre:4 Failed to create file +g0
ORA-15055: unable to connect to ASM instance
ORA-15055: unable to connect to ASM instance
ORA-15055: unable to connect to ASM instance
ORA-15055: unable to connect to ASM instance
--與他的測試錯誤資訊不同。我的版本是10.2.0.4

$ mv ab_+ASM.dat_new ab_+ASM.dat

SYS@xxxxx> create tablespace testtbs datafile '+g0' size 1m;
Tablespace created.

SYS@xxxxx> drop  tablespace testtbs;
Tablespace dropped.

--沒有測試啟動asm例項，如果刪除該檔案如何啟動asm例項呢？

--有一些人看一些檔案不順眼，可能會刪除，比如OMF建立的資料檔案，我就遇到這種情況。在生產系統做這些操作一定要慎之又慎！!