由於沒太多跡象顯示10g 上有類似的問題 , 從oracle support 看到11g 新增ASM空間有可能因為此BUG 造成DB hang 住 , 考量該bug , 目前先朝 Tuning ASM instance 方向處理.
調整後 已正常運作一陣子.
調整後 已正常運作一陣子.
後記與分析 :
發現redo log switch 時, archiver arc0 發生了 KSV master wait 事件 , 也意指
在 ASM file
metadata operation 過程中 ,
遇到該問題 ,
這一段相關的記憶體為
ASM
的db_cache_size
, 故需依照Oracle
建議將其放大
以下為IBM Tuning ASM 文件
Oracle
Parameters
The following
parameters are suggested in the document Oracle Database 10g Release 2
Automatic
Storage Management Overview and Technical Best
Practices:
Parameters to
be included in the spfile for databases using ASM:
1.
Increase Processes by 16
2.
Increase Large_Pool by 600k
3.
Increase Shared Pool by (1M per
100GB of usable space) +
Parameters to
be included in the spfile of the ASM instances:
1.
ASM_POWER_LIMIT=1
The Best
Practices guide suggests this value to make ASM rebalance operations a low
priority;
however, this can potentially cause rebalance operations to occur during peak
volume
times. This parameter can also be set to 0 to prevent accidental
rebalance
operations
from occurring during peak loads, which may be preferable for many
environments. This parameter can be raised specifically when
rebalancing is desired.
2.
Processes=25 + 15n, where “n” is the number of databases which will use ASM.
==>
tuning
建議計算如下:
vi
/oracle/admin/+ASM/pfile
processes=70
(有三個instances ,
test , pdsms , RMAN , processes=25+ 15*3 =70 )
large_pool_size=60M
shared_pool_size=64M ( ASM total disk size : 6.2TB ==>
shared pool : 62MB + 2MB=64MB)
ASM_POWER_LIMIT=1 ==> default value
以下為Oracle 原廠tuning 建議:
Oracle
Database 11g Release 1 and
10g Release 2
Automatic
Storage Management Overview and Technical Best Practices (ASM_11gR1_BestPractices_v34.pdf)
Processes =
25 + (10 + [max number of concurrent database file creations, and file extend
operations possible] )*n
The number n is the number of databases connecting to
ASM
processes= 25
+ (10 + 80) * 2 =205 , 80 由datafiles
數量 加總 logfile
數量得來 , 假如你的環境只有10 個datafile 跟 6 個redo log , 可將80 替換為 16。
shared_pool_size=128M
large_pool_size=12M
db_cache_size=64M
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