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Home -> Community -> Usenet -> c.d.o.server -> Re: Archiver question
It doesn't. It is smart enough to parallelize and get part of the log
from one member and part from the other!
>From an old O7 faq:
"Having multiple members to a logfile group is also advisable. If
there
are multiple members, all members in a group are used to perform the
archive process. Assuming that there are three members, the first
chunk
is read from one of the members and is being written to the archive
while
reading a second chunk from second member, then a third chunk from
third
member, then back to first and the process continues in round robin
fashion.
If a corruption is found in one of the members, it is validated (read
again)
and if the corruption still exists, reading from that member is stopped
and the rest are used.
This is one of the big benefits of using multiple members instead of
mirroring at o/s level. Oracle knows about the multiple members so it
can
optimize on archiving, but it does not know about the mirrors. One
other big
benefit with using multiple members is that a separate write is issued
for
each member, so the odds of having a totally corrupted redo log is
diminished (corruption written to one mirror will usually propagate
over to
all other copies).
"
I have personally seen it figure out and overcome fairly severe corruption problems in recent versions, with no noticeable effect to users. But definitely check your alert log every day, there would have been a big effect one time if I hadn't noticed the messages about the failing hardware in time.
jg
-- @home.com is bogus. ohnohackers! http://www.signonsandiego.com/uniontrib/20050418/news_lz1b18hacker.htmlReceived on Tue Apr 19 2005 - 17:32:26 CDT
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