Cache Fusion Recovery
星期二, 四月 1st, 2008RAC环境下实例崩溃恢复的几种情况。
下介绍下文章中的几个缩写的含义：
After an instance dies and the failure is detected, the SMON process of a surviving
instance will start the first pass log read of the failed instance’s redo thread.
SMON will merge the redo thread ordered by SCN to ensure that changes are written in
an orderly fashion. SMON will also find BWR (block written records) in the redo stream
and remove entries that are no longer needed for recovery because they were past
images of blocks already written to disk. The final product of the first pass log
read is a recovery set that only contains blocks modified by the failed instance
with no subsequent BWR to indicate that the blocks were later written. Each entry
in the recovery list is ordered by first-dirty SCN to specify the order to acquire
instance recovery locks. The recovering SMON process will then inform each lock
element’s master node for each block in the recovery list that it will be taking
ownership of the block and lock for recovery. This is handled differently depending
on ownership of the lock element as described below:
