ORA-00821: Specified value of sga_target 3072M is too small, needs to be at least 12896M，ora-008213072m

ORA-00821: Specified value of sga_target 3072M is too small, needs to be at least 12896M，ora-008213072m

    在測試PlateSpine克隆的數據庫服務器時，由於資源有限，克隆過來的數據庫服務器只給了9G的內存，結果在測試時，老是會出現OOMkiller導致宕機,即out of memory killer,是linux下面當內存耗盡時的的一種處理機制。當內存較少時，OOM會遍歷整個進程鏈表，然後根據進程的內存使用情況以及它的oom score值最終找到得分較高的進程，然後發送kill信號將其殺掉。 於是調整了一下sga_target和sga_max_size這兩個參數，結果重啟的時候悲劇了:

[oracle@mylnx01 ~]$ sqlplus / as sysdba

SQL*Plus: Release 10.2.0.5.0 - Production on Thu Dec 15 09:28:11 2016

Copyright (c) 1982, 2010, Oracle.  All Rights Reserved.

Connected to an idle instance.

SQL> startup

ORA-00821: Specified value of sga_target 3072M is too small, needs to be at least 12896M

SQL> startup nomount

ORA-00093: _shared_pool_reserved_min_alloc must be between 4000 and 0

SQL>

出現這個這個錯誤，突然想起來這個服務器設置過shared_pool_size參數，於是生成pfile，檢查initGSP.ora，如下所示，

SQL> create pfile='/u01/app/oracle/product/10.2.0/db_1/dbs/initGSP.ora' from spfile;

File created.

手工將.shared_pool_size設置為0， 然後啟動數據庫實例，問題解決。如下所示：

SQL> startup pfile='/u01/app/oracle/product/10.2.0/db_1/dbs/initGSP.ora'

ORACLE instance started.

Total System Global Area 3221225472 bytes

Fixed Size                  2099752 bytes

Variable Size             637535704 bytes

Database Buffers         2533359616 bytes

Redo Buffers               48230400 bytes

Database mounted.

Database opened.

SQL> exit