oracle 10G ASM_POWER_LIMIT与Rebalance

文档地址：http://docs.oracle.com/cd/B19306_01/server.102/b14231/storeman.htm#i1027260

 

   If the POWER clause is not specified in anALTER DISKGROUP command, or when rebalance isimplicitly invoked by adding or dropping a disk, the rebalancepower defaults to the value of theASM_POWER_LIMITinitialization parameter.

 

    Youcan adjust this parameter dynamically. The higher the limit, thefaster a rebalance operation may complete. Lower values causerebalancing to take longer, but consume fewer processing and I/Oresources. This leaves these resources available for otherapplications, such as the database. The default value of 1minimizes disruption to other applications.

   

    Theappropriate value is dependent upon your hardware configuration aswell as performance and availability requirements.

    If arebalance is in progress because a disk is manually orautomatically dropped, increasing the power of the rebalanceshortens the window during which redundant copies of that data onthe dropped disk are reconstructed on other disks.

    TheV$ASM_OPERATION view provides information that can beused for adjustingASM_POWER_LIMIT and the resultingpower of rebalance operations. TheV$ASM_OPERATIONview also gives an estimate in the EST_MINUTES columnof the amount of time remaining for the rebalance operation tocomplete. You can see the effect of changing the rebalance power byobserving the change in the time estimate.