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GCS on grid control graph is high and write data slowly

Surachart Opun
Surachart Opun Member Posts: 1,662
edited Apr 5, 2007 11:45AM in Real Application Clusters
We writed more data to Oracle RAC 10.2 + ASM on Redhat.
It's slowly. When we check grap on Grid Control, we found high stat on "Global Cache Block Access Latency".

How can I tune or investigate?

###remark
Oracle Cluster 4 nodes (10.2 + ASM on redhat 4)
interconnect CAT 6 (1G) and use bonding

Comments

  • 557563
    557563 Member Posts: 5
    Just to be certain, how slow and which part of the Global Cache component:

    AWR Report threshholds are (lower boundary - typical - upper boundary)
    Avg time to process cr block request 0.1 - 1 - 10
    Avg Global Cache cr block receive times 0.3 - 4 - 12
    Avg time to process current block request 0.1 - 3 - 23
    Avg Global cache current block receive time 0.3 - 8 - 30


    You might be losing blocks? I have a link to this article...
    http://www.dba-oracle.com/real_application_clusters_rac_grid/cache_stats.htm

    I modified the query found at the link above for more nodes:

    SELECT A.INST_ID "Node ID",
    (select B.VALUE from GV$SYSSTAT B where B.inst_ID=A.INST_ID and B.NAME='gc blocks lost') "GC BLOCKS LOST",
    (select C.VALUE from GV$SYSSTAT C where C.inst_ID=A.INST_ID and C.NAME='gc blocks corrupt') "GC BLOCKS CORRUPT"
    FROM GV$SYSSTAT A
    group by A.INST_ID
    order by 1;

    Each should come back zero or close to zero. If it doesn't then check with your Linux admins to tune to the interface settings. A tuning link is also in the above URL.
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