Friday, October 16, 2009

OLTP database becomes more critical to manage security in this high tech market. It is very important to prevent data hacking from your database.
How to secure your database using advance and hidden feature of Oracle? Dbametrix provides tips for how to enable hidden auditing using undocumented Oracle 11g new feature. It would help you to make secure shield to your important and critical database.

Please watch following article is best for viewing.

http://www.sooperarticles.com/technology-articles/databases-articles/how-audit-database-maintain-high-security-alert-system-using-oracle-11g-new-feature-18443.html

Data Block Buffer transferred across the instances in Oracle RAC During cache fusion

Hi frineds,

Data Block Buffer transferred across the instances in Oracle RAC During cache fusion

Superb quiz has been created for knowledge sharing. Kindly check and participate.

http://www.quibblo.com/quiz/aWdH21C/Data-Block-Buffer-transferred-across-the-instances-in-Oracle-RAC-During-cache-fusion

Article found from following site.

  • http://www.dbametrix.com
  • What is LMS process in Oracle RAC database

    What is LMS process in Oracle RAC databases?

    LMS process called as Lock Manager Server Process , also called the GCS (Global
    Cache Services) process. Main work of this process is to transport blocks across
    to the nodes of Oracle RAC for ¡§cache fusion¡¨ supportability. If any consistent
    read request found from another connected node then LMS process makes consistent
    read image of block and transport it to across the nodes for full feeling
    client¡¦s consistent read request. This images transports using High Speed
    Interconnect process to and from remote nodes.

    If we are using 8K block size then transporting consistent read images across to
    remote node using HSI using interconnect protocall becomes more busy and high
    CPU utilization. Which we can check from AWR reports, Statspack reports or Wait
    event called ¡§global Cache Services¡¨ wait event. If this wait event consumes
    more CPU utilization and simultaneously found performance degradation of Oracle
    Database causes ¡§cache fusion¡¨ and consistent read request traportation across
    to RAC nodes.

    How to avoid this kind of performance degradation of Oracle RAC?


    In Oracle Real Application Clusters, the cluster interconnect is a dedicated or
    stand alone network This interconnect network is using to communicate the
    connected nodes across the clustering of RAC.

    Ethernet is using in networking of Cluster interconnect protocol. Ethernet¡¦s
    default frame size of 45-1500 bytes is transfering unit between the all
    participant of nodes and hosts. If request of tranferring data is larger than
    1500 bytes then it will be split ed into smaller units and send multiple packets
    across to nodes using interconnect because lower range is 45 to 46 and upper
    limit of data is 1500 (maximum transfer unit) bytes.

    Deployment of Jumbo Frames is very best option to such drastic situation of
    performance bottleneck. Jumbo Frames allows Ethernet packets to be sent in a
    larger size rather than default size.

    Generally Ethernet frames use a 1500 bytes size. Jumbo Frames allows this to be
    extended to 9000 bytes frame. This 9000 byte frame actually allow to send or
    transport 8k or larger block size data into single request of packets across to
    remote nodes instead of multiple frames which size default is 1500 bytes. This
    scenario is improving performance of RAC nodes specially ¡§global Cache
    Services¡¨ wait event because it directly connected with consistent read request
    block image transporting across to remote nodes using interconnect protocol.

    Multi block read request (called full table scan) is also affecting with same
    scenario while we are using lower bound limit or default bound limit of MTU
    (maximum transfer unit) of interconnect of RAC. It is also stripping data in
    smaller units and send across to RAC connected nodes for ¡§cache fusion¡¨ or
    ¡§cr global cache request¡¨. It is most targeting for deployment of same Jumbo
    Frames.


    If small data is being transported then Jumbo Frames are not efficient and not
    recommended.


    Generally it is advisable to deploy for large amount of CR image transfer (cache
    fusion) using LMS process (means Global Cache Services) and your data block size
    is 8k or larger. But it is not advisable to implement in general IP address of
    Ethernet card of server otherwise it may be degrade performance while small
    packet request is processing.

    Said article from following source.
  • http://www.dbametrix.com
  •