High "log file sync" Waits in Statspack, - Online Redo Logs on Mounted File system of SAN Storage

From: VIVEK_SHARMA <VIVEK_SHARMA_at_infosys.com>
Date: Sat, 12 Jan 2008 07:26:46 +0530
Message-ID: <69E1360E54B50C4A828A136C158E4742036A70766F@BLRKECMBX02.ad.infosys.com>

Folks

During a Benchmark Run of OLTP Transactions very High "log file sync" wait is occuring Storage Box - Sun StoreEdge 9990V (Hitachi SAN) Online Redo logfiles exist on Mounted Filesystem on a LUN / Volume of 4+4 Hard Disks , (RAID 1+0 Type) Hard Disk - 15 K RPM
Storage Cache - 128 GB
Online Redo Logfile size 750 MB
log_buffer= 4M

Oracle 10.2.0.3
Solaris 10

Qs On the Storage Box, should a few of its HBA Controllers & respective Ports be assigned dedicatedly only to the online Redo LUN / Volume? Qs Should Online Redo Logiles be moved to RAW Devices on the SAN Storage? Qs Any advisable init.ora parameters?

Qs How should this issue be approached?

Will share Statspack as needed

Cheers & Thanks

P.S.

Top 5 Timed Events                                                 Avg    %Total

~~~~~~~~~~~~~~~~~~                                                 wait   Call

Event                                     Waits        Time (s)    (ms)   Time

----------------------------------------- ------------ ----------- ------ ------

log file sync                             3,511,274    328,288     93     73.6

SQL*Net break/reset to client             732,491      49,120      67     11.0

CPU time 31,699 7.1

latch: virtual circuit queues 1,099,453 10,695 10 2.4

db file parallel write                    3,253,478    9,535       3      2.1

-------------------------------------------------------------



Host CPU (CPUs: 80)

~~~~~~~~ Load Average

Begin End User System Idle WIO WCPU

  • ------- ------- ------- ------- ------- --------
                9.13    1.79

               16.35   23.30   60.35    0.00    2.79



Load Profile     Per Second Per  Transaction

~~~~~~~~~~~~     --------------- ---------------

Redo size:       3,143,457.88    4,121.10

...

Block changes: 15,320.88 20.09

...

Physical writes: 2,176.56 2.85

User calls: 14,769.89 19.36

...

Logons: 3.55 0.00

Executes: 12,950.32 16.98

Transactions: 762.77

  • CAUTION - Disclaimer ***************** This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely for the use of the addressee(s). If you are not the intended recipient, please notify the sender by e-mail and delete the original message. Further, you are not to copy, disclose, or distribute this e-mail or its contents to any other person and any such actions are unlawful. This e-mail may contain viruses. Infosys has taken every reasonable precaution to minimize this risk, but is not liable for any damage you may sustain as a result of any virus in this e-mail. You should carry out your own virus checks before opening the e-mail or attachment. Infosys reserves the right to monitor and review the content of all messages sent to or from this e-mail address. Messages sent to or from this e-mail address may be stored on the Infosys e-mail system. ***INFOSYS******** End of Disclaimer ********INFOSYS*** -- http://www.freelists.org/webpage/oracle-l
Received on Fri Jan 11 2008 - 19:56:46 CST

Original text of this message