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  Oracle Tips by Burleson

SCSI Runs

The SCSI runs required from June 2, 2004 to July 30, 2004 to complete. This 58 day period encompassed seven full query runs and a single partial run. This was with queries running as close as possible to 24X7, between equipment failures and connectivity issues. During the test, the initial 2-disk SCSI array failed during the second query set run. This required a database rebuild and reload on the provided ATA array. After the SCSI failure, the entire initial query run had to be repeated, compared to the SCSI results and the decision was made at that time to discard the SCSI results and continue with the ATA array.

The initial nologgingand noarchivingruns performed so poorly that nologging and noarchiveloggingset points were used during the subsequent tests as well to allow the tests to complete in a reasonable amount of time.  This is due to the fact that turning on loggingand archivelogwould further stress the I/O subsystem resulting in even poorer performance. The following issues further complicated the testing:

  • When running the queries against the 100% SCSI/ATA database, query number one would not complete, and after 30 hours it was halted.

  • When running the queries against the 100% SCSI/ATA database, query number four would not complete in 30 hours, and it was halted.

  • When running against the 100% SCSI/ATA database query number produced the error codes shown below. It then terminated the session causing all subsequent queries to fail in run number one, requiring a restart:

Sun Jun  6 11:43:16 2004
Errors in file /home/oracle/admin/dss/udump/dss_ora_615.trc:
ORA-00600: internal error code, arguments: [kftts2bz_many_files], [0], [39218], [], [], [], [], []
Sun Jun  6 11:43:17 2004
Errors in file /home/oracle/admin/dss/udump/dss_ora_615.trc:
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-00600: internal error code, arguments: [kftts2bz_many_files], [0], [39218], [], [], [], [], []
Sun Jun  6 11:43:18 2004
Errors in file /home/oracle/admin/dss/udump/dss_ora_615.trc:
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-00600: internal error code, arguments: [kftts2bz_many_files], [0], [39218], [], [], [], [], []
Sun Jun  6 11:43:18 2004
Errors in file /home/oracle/admin/dss/udump/dss_ora_615.trc:
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-00600: internal error code, arguments: [kftts2bz_many_files], [0], [39218], [], [], [], [], []
[oracle@AMD43 bdump]$
[oracle@AMD43 bdump]$ tail -f alert_dss.log
Errors in file /home/oracle/admin/dss/udump/dss_ora_615.trc:
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-00600: internal error code, arguments: [kftts2bz_many_files], [0], [39218], [], [], [], [], []
Sun Jun  6 11:43:18 2004
Errors in file /home/oracle/admin/dss/udump/dss_ora_615.trc:
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-07445: exception encountered: core dump [kghbigasp()+289] [SIGSEGV] [Address not mapped to object] [0x427A8] [] []
ORA-00600: internal error code, arguments: [kftts2bz_many_files], [0], [39218], [], [], [], [], []

  • The queries would run out of temporary space, undo segment space, and generate the above errors if run back-to-back in the same user.  The script running the queries was modified to include a new connect statement before each query, releasing previous undo segments and temp segments for reuse. This was not required in the SSD tests. Each run was actually several smaller runs restarted at the point of failure.

  • During run number two of the initial SCSI test, the array failed after approximately eight days of 24X7 processing. This required the rebuild of the database on the new ATA array.

  • During the final runs, a complete power outage that caused a reassignment of the ATA array address, which resulted in two days of down time. The data was fully recovered through the automated recovery processing and the testing resumed.

  • Several days were also lost due to connectivity issues.

  • Any query that required longer than ~30 hours was terminated and processing restarted at the next query in the file. This was required on queries number one, three, 13, 13a, 17, and 18 in various configurations. The resulting time was set to 1440 minutes (24 hours) and the graph axis set to logarithmic to allow the graphs to show at least some of the shorter query times.


The above book excerpt is from:

Oracle RAC & Tuning with Solid State Disk

Expert Secrets for High Performance Clustered Grid Computing

ISBN 0-9761573-5-7

Donald K. Burleson & Mike Ault

http://www.rampant-books.com/book_2005_2_rac_ssd_tuning.htm

  
 

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