Database on the file system

Hi, Oracle DBA

I have a simple question.

If I choose to put redolog files and database files on the file system, instead of raw devices and when I meet the system crash trouble, I wonder why Oracle can completely make good to recover all database files by redolog files.

I mean, as you may know, data-writing to all files on the file system is generally kept once on kernel cash area so-called the file system buffer and contents in the buffer are periodically flushed to the physical disks by a syncer daemon.
Considering that system crash happen perior to buffer flush, I guess some redolog files may be lost in next fsck phase. (Especially in high-transaction environment, redolog file switching is also high.) In case of loosing redolog files application no longer recover its database, I think. It means it may lost some (many?) transactions.

I wonder why really safe way to put oracle files on the file systems, instead of raw devices...

Thanks,
Yugo Shimada
yugos_at_d1.dion.ne.jp

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Share what you know. Learn what you don't. Received on Wed Jun 23 1999 - 03:15:58 CDT