Ora-00823:specified value of Sga_target greater than sga_max_size

Change sga_max_size when accidentally less than the unit ' M ', the result encountered ORA-00823 caused the database can not start.
1. Modify Sga_max_size parameters in Pfile after creating Spfiel based on Pfile
2. Start the database with Pfile and test normal.
3. Create SPFile according to Pfiel
4. Start the database with SPFile.

Sql>alter SYSTEM SET sga_max_size = 4096 scope=spfile; Less write a m, the damage to the database can not get up

sql> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.

Sql> Startup Nomount
ora-00823:specified value of sga_target greater than sga_max_size

sql> CREATE pfile= '/opt/ora11g/product/11.2.3/db_1/dbs/pfile01.ora ' from SPFILE;
File created.

Sql>!
[Oracle@oradb01 emd]$ vi CREATE pfile= '/opt/ora11g/product/11.2.3/db_1/dbs/pfile01.ora ' from SPFILE;

*.sga_max_size=4096 instead
*.sga_max_size=4096m

sql> startup pfile= '/opt/ora11g/product/11.2.3/db_1/dbs/pfile01.ora '
ORACLE instance started.
Total System Global area 4275781632 bytes
Fixed Size 2266024 bytes
Variable Size 1681919064 bytes
Database buffers 2583691264 bytes
Redo buffers 7905280 bytes
Database mounted.
Database opened.
Sql>!
[Oracle@oradb01 emd]$ cd/opt/ora11g/product/11.2.3/db_1/dbs/

[ORACLE@ORADB01 dbs]$ CP Spfileorcl.ora SPFILEORCL.ORA_BAK01

[Oracle@oradb01 dbs]$ exit
Exit

sql> CREATE spfile= '/opt/ora11g/product/11.2.3/db_1/dbs/spfileorcl.ora ' from pfile= '/opt/ora11g/product/11.2.3/ Db_1/dbs/pfile01.ora ';

sql> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
Sql> Startup
ORACLE instance started.

Total System Global area 4275781632 bytes
Fixed Size 2235208 bytes
Variable Size 1677722808 bytes
Database buffers 2583691264 bytes
Redo buffers 12132352 bytes
Database mounted.
Database opened.