[cgl_discussion] Oracle Clustered Filesystem

Brian Stevens bstevens at redhat.com
Mon Dec 2 13:15:15 PST 2002

Eric.Chacron at alcatel.fr wrote:

>I would like to get something like a summary of what is provided by OCFS
>and possibly compared to what GFS done.
>Do you have such a material ?

No summary prepared. I look at OCFS as a great cluster filesystem in the 
term that eliminates the need to run Oracle's RAC (clustered database) on
raw devices. OCFS then provides a more manageable environment as instead
of making admins map database files and logs to raw devices, they can map
them to files. Consistent with how they run Oracle on a single system.
OCFS does not have to scale as well for applications that thrash the
filesystem cache, since Oracle manages this itself using cache fusion
technology. So while it works well for RAC, OCFS (today) may not
work that well for some applications that are update intensive on the
same file regions.

GFS and OpenGFS are designed to solve both the RAC and general
purpose cluster filesystem problem. My biggest concern with OpenGFS
is that it still needs a fair bit of (re)work based on comments I have
seen, including integration with a robust DLM to not have dependencies
on hardware locking. GFS may have solved all of these problems, but
since it is not open-source I'm not sure.


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