Re: HELP! Cheyenne on-line backup locks Server

From: Sameer Mahajan <sameerm_at_worldnet.att.net>
Date: 1998/01/02
Message-ID: <68hepv$rm6_at_bgtnsc03.worldnet.att.net>#1/1


Hi Tim,

Assumption:
1. By online backup, u mean hot backup of a tablespace. 2. The entire server lockup. U mean that Oracle simple stands still no transaction can take place. Oracle just halts. 3. Ur database is in Archivelog mode.
4. By logs below I mean redo log unless specified.

Note:
When u place the tablespace in hot backup mode the activity on your redo increase. The checkpoint done during the execution of the alter tablespace begin backup command ensures that only blocks that are changed during the hot backup are written to the redo log file. Thus the excessive redo would be generated for data files in hot backup mode.

Further the switch between the logs and the generation of archive log at that moment of time would be higher.

Likely reasons for Oracle to halt in the case u have stated:

  1. Since the logs will fill up faster and would take less time to switch (due to higher activity) by the time it returns back to the same log (remember they are cyclic) the Archiving of that log might not have completed. Result: Oracle is going to wait before it starts overrighting that log again. Solution:1. Increase the number of logs. So that it gives more time to write the archivelog.
  2. Start up the Archiver process (ARCH) to do the archiving. Either set in the init.ora LOG_ARCHIVE_START or issue archive log start from server manager or sqldba.
  3. The disk or the destination where u are archiving gets filled up. Result: Oracle is going to simple stall and wait for u to create more space. Solution: Ensure that u have sufficient space in ur archive destination. This should be set under init.ora LOG_ARCHIVE_DEST

U could check both these parameters from v$parameters. 3. Check the alert.log that might give u some hint as to what is the problem at that

   moment of time.

HTH Regards

Sameer Mahajan
sameermj_at_usa.net

Tim Fulton <Fultont_at_IngramIndustries.com> wrote in article <34aa8435.0_at_199.0.68.3>...
> When performing an on-line backup of an Oracle database, the entire
 server
> locks up. The only way to clear it is to shut the server down and
 restart.
> Upon restarting Oracle, the database must be recovered. This lock occurs
 on
> a different tablespace each time. Any idea what is causing the problem?
>
> Regards,
> Tim
>
> Fultont_at_Ingramindustries.com
>
>
>
>
Received on Fri Jan 02 1998 - 00:00:00 CET

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