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Filip Ekberg
Asked: 2009-10-22 00:04:25 +0800 CST

Accidently overwrote system.dbf - What now?

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I accidentally overwrote system.dbf in /usr/lib/oracle/xe/oradata/XE/system.dbf

Well I did not actually do it accidentally, however I overwrote it because of other failures in the database.

And when I try running the following:

SQL> shutdown
ORA-01109: database not open


Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area  289406976 bytes
Fixed Size                  1258488 bytes
Variable Size              92277768 bytes
Database Buffers          192937984 bytes
Redo Buffers                2932736 bytes
Database mounted.
ORA-01589: must use RESETLOGS or NORESETLOGS option for database open

Now I want to try to Recover the database because starting it in mounted or standard surely doesn't work.

SQL> recover database using backup controlfile;
ORA-00283: recovery session canceled due to errors
ORA-01110: data file 1: '/usr/lib/oracle/xe/oradata/XE/system.dbf'
ORA-01122: database file 1 failed verification check
ORA-01110: data file 1: '/usr/lib/oracle/xe/oradata/XE/system.dbf'
ORA-01206: file is not part of this database - wrong database id

How do I solve this? Is it even possible?

My "real" problem was that I ran the /etc/init.d/oracle-xe configure and it overwrote my old configuration and probably removed passwords and such so my tables were gone, however I found the mytablespace.dbf so I hope that it is possible to recover?

Please shed some light on this.

database

2 Answers

  1. Best Answer

    Do you have a backup of your database? Overwriting the SYSTEM tablespace data files would necessitate a complete restore from backup.

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  2. As I have no experience of Oracle, I don't know at all if this applies. But if the file was opened by a process, and that process is still running, you would be able to recover it by accessing it in the /proc filesystem. 

    # ls -l /proc/13646/fd
total 0
lrwx------ 1 root root 64 Apr 13 21:43 0 -> /dev/null
lrwx------ 1 root root 64 Apr 13 21:43 1 -> /dev/null
lrwx------ 1 root root 64 Apr 13 21:43 2 -> /dev/null
lrwx------ 1 root root 64 Apr 13 21:43 3 -> socket:[38094]
l-wx------ 1 root root 64 Apr 13 21:43 4 -> /var/log/openvpn-status-server.log
lrwx------ 1 root root 64 Apr 13 21:43 5 -> /etc/openvpn/ipp.txt
lrwx------ 1 root root 64 Apr 13 21:43 6 -> socket:[38099]
lrwx------ 1 root root 64 Apr 13 21:43 7 -> /dev/net/tun

    Lets remove one of them!

    # rm /var/log/openvpn-status-server.log
# ls /var/log/openvpn-status-server.log
ls: cannot access /var/log/openvpn-status-server.log: No such file or directory

    Ok, removed, ls again:

    # ls -l /proc/13646/fd/4 
l-wx------ 1 root root 64 Apr 13 21:43 /proc/13646/fd/4 -> /var/log/openvpn-status-    server.log (deleted)

    There it is, deleted but still held.

    # cp /proc/13646/fd/4 myrecover.txt
# ls -l myrecover.txt 
-rw------- 1 root root 359 Apr 13 21:45 myrecover.txt

    Sure enough, my dear old openvpn-status-server.log was recovered!

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