ORA-00845 MEMORY_TARGET not supported on this system

ORA- 00845: MEMORY_TARGET not supported on this system

我建立虛拟機的時候 選擇的是8G的記憶體，但是檢查的時候報錯，我隻有4G提示 Swap分區不夠， 其實是可以使用DD指令解決的。  GG 同步不起。

解決Linux上11g的ORA-00845錯誤

下午想把一個11.2.0.2執行個體的memory_target AMM記憶體初始化參數修改到2000M，改好後重新開機發現執行個體起不來了，出現了ORA-00845錯誤:

[[email protected] ~]$ 
[[email protected] ~]$ sqlplus  / as sysdba

SQL*Plus: Release 11.2.0.2.0 Production on Tue May 3 19:43:50 2011

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

Connected to an idle instance.

SQL> startup nomount;
ORA-00845: MEMORY_TARGET not supported on this system

======================= ALERT.LOG======================

Starting ORACLE instance (normal)
WARNING: You are trying to use the MEMORY_TARGET feature. 
This feature requires the /dev/shm file system to be mounted for at least 2097152000 bytes. 
/dev/shm is either not mounted or is mounted with available space less than this size. 
Please fix this so that MEMORY_TARGET can work as expected. 
Current available is 1871466496 and used is 200790016 bytes. 
Ensure that the mount point is /dev/shm for this directory.
memory_target needs larger /dev/shm      

看起來是因為采用了Automatic Memory Management的特性，是以Oracle采用了一種基于POSIX的共享記憶體使用風格，在AMM中Oracle不像之前版本那樣利用”一整塊”記憶體作為SGA，而是使用一塊塊小的”chunk”，以滿足SGA與PGA之前交換記憶體的目的

針對上述ORA-00845錯誤，我們需要修改映射記憶體檔案夾/dev/shm的裝載參數，針對正在運作的Linux作業系統，可以remount這個tmpfs裝載點，如:

[[email protected] ~]# umount /dev/shm
umount: /dev/shm: device is busy
umount: /dev/shm: device is busy

[[email protected] ~]# ls /dev/shm
JOXSHM_EXT_0_PROD1_8323079   JOXSHM_EXT_25_PROD1_8323079  ora_+ASM1_7569414_11  
JOXSHM_EXT_10_PROD1_8323079  JOXSHM_EXT_26_PROD1_8323079  ora_+ASM1_7569414_12  
............

/* 可以看到如果ASM執行個體也使用AMM的話同樣會在/dev/shm目錄下産生記憶體映像 
    為了umount該裝載點，我們不得不首先shutdown ASM instance ! */

[[email protected] ~]# su - grid
[[email protected] ~]$ sqlplus  / as sysdba

SQL*Plus: Release 11.2.0.2.0 Production on Tue May 3 20:05:24 2011

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

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options

SQL> shutdown immediate;
ORA-01031: insufficient privileges
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options
[[email protected] ~]$ sqlplus  / as sysasm

SQL*Plus: Release 11.2.0.2.0 Production on Tue May 3 20:05:32 2011

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

Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options

SQL> shutdown immediate;
ORA-15097: cannot SHUTDOWN ASM instance with connected client (process 1576)
SQL> shutdown abort;
ASM instance shutdown
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - 64bit Production
With the Real Application Clusters and Automatic Storage Management options

[[email protected] ~]# umount /dev/shm

[[email protected] ~]# mount -t tmpfs shmfs -o size=4000m /dev/shm

/* 這裡的size指定了shm目錄的裝載大小，4000m可能對你的系統仍然不夠，
    那麼你有理由設一個更大的值  */


[[email protected] ~]# mount|grep shmfs
shmfs on /dev/shm type tmpfs (rw,size=4000m)

Startup ASM...........

[[email protected] ~]# su - oracle
[[email protected] ~]$ sqlplus  / as sysdba

SQL*Plus: Release 11.2.0.2.0 Production on Tue May 3 20:09:40 2011

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

Connected to an idle instance.

SQL> startup nomount;
ORACLE instance started.

Total System Global Area 2087780352 bytes
Fixed Size                  2228072 bytes
Variable Size            1476395160 bytes
Database Buffers          603979776 bytes
Redo Buffers                5177344 bytes

/* 執行個體啟動成功！ */      

上述umount/mount的方式隻在作業系統的此次生命周期中生效，如果重新開機的話shmfs目錄仍會以預設方式裝載；如果需要永久生效的話，我們需要修改系統參數檔案/etc/fstab中的shm條目:

/* 修改前的shm裝載參數 */

[[email protected] ~]# grep shm /etc/fstab 
tmpfs                   /dev/shm                tmpfs   defaults        0 0

/* 修改後的shm裝載參數 */

[[email protected] ~]# grep shm /etc/fstab 
tmpfs                   /dev/shm                tmpfs   rw,size=4000m   0 0      

參考：

oracle啟動報錯：ORA- 00845: MEMORY_TARGET not supported on this system

今天啟動oracle的時候，報錯

[[email protected] ~]#su - oracle

[[email protected] ~]$lsnrctl start

lsnrctl: error while loading shared libraries: /u01/app/oracle/product/11.2.0/db_1/lib/libclntsh.so.11.1: cannot restore segment prot after reloc: Permission denied

解決辦法：在root使用者下執行以下指令

[[email protected] ~]# setenforce 0

[[email protected] ~]#su - oracle

[[email protected] ~]$lsnrctl start

LSNRCTL for Linux: Version 11.2.0.1.0 - Production on 20-SEP-2012 19:03:03

Copyright (c) 1991, 2009, Oracle.  All rights reserved.

Starting /u01/app/oracle/product/11.2.0/db_1/bin/tnslsnr: please wait...

TNSLSNR for Linux: Version 11.2.0.1.0 - Production

Log messages written to /u01/app/oracle/diag/tnslsnr/localhost/listener/alert/log.xml

Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost.localdomain)(PORT=1521)))

Connecting to (ADDRESS=(PROTOCOL=tcp)(HOST=)(PORT=1521))

STATUS of the LISTENER

------------------------

Alias                     LISTENER

Version                   TNSLSNR for Linux: Version 11.2.0.1.0 - Production

Start Date                20-SEP-2012 19:03:04

Uptime                    0 days 0 hr. 0 min. 1 sec

Trace Level               off

Security                  ON: Local OS Authentication

SNMP                      OFF

Listener Log File         /u01/app/oracle/diag/tnslsnr/localhost/listener/alert/log.xml

Listening Endpoints Summary...

 (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost.localdomain)(PORT=1521)))

The listener supports no services

The command completed successfully

問題解決。

[[email protected] ~]$ sqlplus / as sysdba

SQL> startup

報錯：ORA-00845: MEMORY_TARGET not supported on this system

問題定位：安裝資料庫時或者修改了參數MEMORY_TARGET或者SGA_TARGET的大小。

 SGA參數的大小超過了作業系統/dev/shm的大小。

 linux安裝完後預設/dev/shm為實體記憶體的一半。

技術背景：linux大記憶體支援（Very Large Memory）中，使用了shmfs/tmpfs選項，ramfs也可以。

 /dev/shm目錄挂載類型為tmpfs，此共享記憶體用于交換，尤其對于大檔案優勢明顯。

 相對于ramfs，tmpfs的優勢在于動态調整實體記憶體的占用，而ramfs不能調整。

 /dev/shm與swap的差別：shm基于記憶體的檔案系統，swap基于硬碟的檔案系統。

解決方法：

1、調整MEMORY_TARGET（11G）或者SGA_TARGET（9i，10G）大小（不建議）。

2、調整/dev/shm的大小。

 修改/etc/fstab，重新mount /dev/shm，然後就可以啟動資料庫了。

（1）檢視/dev/shm 大小

 df -k /dev/shm

 Filesystem 1K-blocks Used Available Use% Mounted on

 tmpfs 4089416 0 4089416 0% /dev/shm

（2）調整/dev/shm大小

 vi /etc/fstab

 #tmpfs /dev/shm tmpfs defaults 0 0

 tmpfs /dev/shm tmpfs defaults,size=10240M 0 0

（3）重新加載

 umount /dev/shm

 mount /dev/shm

 df -k /dev/shm

（4）登陸測試

 sqlplus / as sysdba

至此問題得到解決。