RE: Slow read on OCFS Windows

Steve,
Didn't know they had ocfs for Windows!?

I use (have only used) ocfs on Linux.
It works, but is IMHO much slower than EXT3 and RAW.

>>Can anyone confirm if this copy attempt is expected behavior
What do you mean by "copy".
In the OCFS-Linux world "copy" can not / should not be done by "cp" but rather by using the o_direct as part of the OCFS utils; cp --o_direct=yes /o04/arch/orcl/arch_orcl_T1_S136.arc /o01/arch/

--http://oss.oracle.com/projects/ocfs/dist/documentation/RHAS_best_practices.html Copying files (i.e. cp --o_direct ..., dd o_direct=yes ..., tar --o_direct ...) from an OCFS partition requires the application of fileutils and tar patches that provide direct_io write capability. o_direct enabled versions of these utilities are available from MetaLink (http://metalink.oracle.com) as patches:

• Patch 2883583: fileutils-4.1-4.2.i386.rpm
• Patch 2913284: tar-1.13.25-9.i386.rpm

---OTN
Update on OCFS
by Wim Coekaerts

When the database opens a file on OCFS, it opens it with an extra flag, O_DIRECT. When a file on any node is opened with O_DIRECT, regular file access is not allowed. Attempting a cp, an md5sum, or a dd through the standard OS tools will fail with -EPERM. If you want to be able to use cp or dd while the database is up and running—to make a hot backup, for instance—you need to download updated fileutils packages or use RMAN.

These updated fileutils—cp, dd, and the like—take an option, o_direct=yes, that makes the tool also use 0_direct when opening the file.

Using O_direct makes the filesystem perform better. If you want to use dd or cp, you should also add a large blocksize; the ideal size for OCFS is between 512K and 1MB. For example:

dd o_direct=yes if=/ocfs/foo of=/backup/foo.bak bs=1M

hth

Chris Marquez
Oracle DBA
HEYMONitor™ - heymonitor.com
"Oracle Monitoring & Alerting Solution"

-----Original Message-----
From: oracle-l-bounce_at_freelists.org on behalf of Steve Montgomery Sent: Thu 5/12/2005 1:56 PM
To: Oracle-L_at_FreeLists.org
Subject: Slow read on OCFS Windows  

We are recovering from a SAN failure as we put things back together=20 we notice that copying database files from NFTS on one server to OCFS on the Windooze cluster fails, even a 1 k file. We can copy by pulling the files to the OCFS lun ok then . I'm suspicious that the SAN is not completetly healthy. Can anyone confirm if this copy attempt is expected behavior. SAN is CX 600 btw

thanks

steve

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