ext3 data=ordered - good enough for oracle?

Johann Lombardi johann.lombardi at bull.net
Tue Apr 25 14:49:50 UTC 2006


Hi Herta,

> Thanks for the reply, Johann, but given that Oracle is still using the
> filesystem (unless you use raw devices or ASM), what good does caching
> do in case of a hard crash?

It's handled at the application level.

> The O_SYNC and O_DIRECT would help.  Is there any way to verify that
> this is what Oracle actually does?

It does:
http://www.oracle.com/technology/tech/linux/htdocs/oracleonlinux_faq.html#8
http://asktom.oracle.com/pls/ask/f?p=4950:8:::::F4950_P8_DISPLAYID:618260965466
(thread entitled "Commited data not "guaranteed" ?")
http://www.redhat.com/magazine/013nov05/features/oracle/

You can google "Oracle O_SYNC" for more pointers (or do it yourself with strace
or gdb).

Johann




More information about the Ext3-users mailing list