RE: High "log file sync" Waits in Statspack, - Online Redo Logs on Mounted File system of SAN Storage
Date: Sat, 12 Jan 2008 07:47:33 +0530
Message-ID: <69E1360E54B50C4A828A136C158E4742036A707672@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
...
Executes: 12,950.32 16.98
Transactions: 762.77
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